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    1 News for the tz database
    2 
    3 Release 2022g - 2022-11-29 08:58:31 -0800
    4 
    5   Briefly:
    6     The northern edge of Chihuahua changes to US timekeeping.
    7     Much of Greenland stops changing clocks after March 2023.
    8     Fix some pre-1996 timestamps in northern Canada.
    9     C89 is now deprecated; please use C99 or later.
   10     Portability fixes for AIX, libintl, MS-Windows, musl, z/OS
   11     In C code, use more C23 features if available.
   12     C23 timegm now supported by default
   13     Fixes for unlikely integer overflows
   14 
   15   Changes to future timestamps
   16 
   17     In the Mexican state of Chihuahua, the border strip near the US
   18     will change to agree with nearby US locations on 2022-11-30.
   19     The strip's western part, represented by Ciudad Juárez, switches
   20     from -06 all year to -07/-06 with US DST rules, like El Paso, TX.
   21     The eastern part, represented by Ojinaga, will observe US DST next
   22     year, like Presidio, TX.  (Thanks to Heitor David Pinto.)
   23     A new Zone America/Ciudad_Juarez splits from America/Ojinaga.
   24 
   25     Much of Greenland, represented by America/Nuuk, stops observing
   26     winter time after March 2023, so its daylight saving time becomes
   27     standard time.  (Thanks to Jonas Nyrup and Jürgen Appel.)
   28 
   29   Changes to past timestamps
   30 
   31     Changes for pre-1996 northern Canada (thanks to Chris Walton):
   32 
   33       Merge America/Iqaluit and America/Pangnirtung into the former,
   34       with a backward compatibility link for the latter name.
   35       There is no good evidence the two locations differ since 1970.
   36       This change affects pre-1996 America/Pangnirtung timestamps.
   37 
   38       Cambridge Bay, Inuvik, Iqaluit, Rankin Inlet, Resolute and
   39       Yellowknife did not observe DST in 1965, and did observe DST
   40       from 1972 through 1979.
   41 
   42       Whitehorse moved from -09 to -08 on 1966-02-27, not 1967-05-28.
   43 
   44     Colombia's 1993 fallback was 02-06 24:00, not 04-04 00:00.
   45     (Thanks to Alois Treindl.)
   46 
   47     Singapore's 1981-12-31 change was at 16:00 UTC (23:30 local time),
   48     not 24:00 local time.  (Thanks to Geoff Clare via Robert Elz.)
   49 
   50   Changes to code
   51 
   52     Although tzcode still works with C89, bugs found in recent routine
   53     maintenance indicate that bitrot has set in and that in practice
   54     C89 is no longer used to build tzcode.  As it is a maintenance
   55     burden, support for C89 is planned to be removed soon.  Instead,
   56     please use compilers compatible with C99, C11, C17, or C23.
   57 
   58     timegm, which tzcode implemented in 1989, will finally be
   59     standardized 34 years later as part of C23, so timegm is now
   60     supported even if STD_INSPIRED is not defined.
   61 
   62     Fix bug in zdump's tzalloc emulation on hosts that lack tm_zone.
   63     (Problem reported by Đoàn Trần Công Danh.)
   64 
   65     Fix bug in zic on hosts where malloc(0) yields NULL on success.
   66     (Problem reported by Tim McBrayer for AIX 6.1.)
   67 
   68     Fix zic configuration to avoid linkage failures on some platforms.
   69     (Problems reported by Gilmore Davidson and Igor Ivanov.)
   70 
   71     Work around MS-Windows nmake incompatibility with POSIX.
   72     (Problem reported by Manuela Friedrich.)
   73 
   74     Port mktime and strftime to debugging platforms where accessing
   75     uninitialized data has undefined behavior (strftime problem
   76     reported by Robert Elz).
   77 
   78     Check more carefully for unlikely integer overflows, preferring
   79     C23 <stdckdint.h> to overflow checking by hand, as the latter has
   80     had obscure bugs.
   81 
   82   Changes to build procedure
   83 
   84     New Makefile rule check_mild that skips checking whether Link
   85     lines are in the file 'backward'.  (Inspired by a suggestion from
   86     Stephen Colebourne.)
   87 
   88 
   89 Release 2022f - 2022-10-28 18:04:57 -0700
   90 
   91   Briefly:
   92     Mexico will no longer observe DST except near the US border.
   93     Chihuahua moves to year-round -06 on 2022-10-30.
   94     Fiji no longer observes DST.
   95     Move links to 'backward'.
   96     In vanguard form, GMT is now a Zone and Etc/GMT a link.
   97     zic now supports links to links, and vanguard form uses this.
   98     Simplify four Ontario zones.
   99     Fix a Y2438 bug when reading TZif data.
  100     Enable 64-bit time_t on 32-bit glibc platforms.
  101     Omit large-file support when no longer needed.
  102     In C code, use some C23 features if available.
  103     Remove no-longer-needed workaround for Qt bug 53071.
  104 
  105   Changes to future timestamps
  106 
  107     Mexico will no longer observe DST after 2022, except for areas
  108     near the US border that continue to observe US DST rules.
  109     On 2022-10-30 at 02:00 the Mexican state of Chihuahua moves
  110     from -07 (-06 with DST) to year-round -06, thus not changing
  111     its clocks that day.  The new law states that Chihuahua
  112     near the US border no longer observes US DST.
  113     (Thanks to gera for the heads-up about Chihuahua.)
  114 
  115     Fiji will not observe DST in 2022/3.  (Thanks to Shalvin Narayan.)
  116     For now, assume DST is suspended indefinitely.
  117 
  118   Changes to data
  119 
  120     Move links to 'backward' to ease and simplify link maintenance.
  121     This affects generated data only if you use 'make BACKWARD='.
  122 
  123     GMT is now a Zone and Etc/GMT a link instead of vice versa,
  124     as GMT is needed for leap second support whereas Etc/GMT is not.
  125     However, this change exposes a bug in TZUpdater 2.3.2 so it is
  126     present only in vanguard form for now.
  127 
  128     Vanguard form now uses links to links, as zic now supports this.
  129 
  130   Changes to past timestamps
  131 
  132     Simplify four Ontario zones, as most of the post-1970 differences
  133     seem to have been imaginary.  (Problem reported by Chris Walton.)
  134     Move America/Nipigon, America/Rainy_River, and America/Thunder_Bay
  135     to 'backzone'; backward-compatibility links still work, albeit
  136     with some different timestamps before November 2005.
  137 
  138   Changes to code
  139 
  140     zic now supports links to links regardless of input line order.
  141     For example, if Australia/Sydney is a Zone, the lines
  142       Link Australia/Canberra Australia/ACT
  143       Link Australia/Sydney Australia/Canberra
  144     now work correctly, even though the shell commands
  145       ln Australia/Canberra Australia/ACT
  146       ln Australia/Sydney Australia/Canberra
  147     would fail because the first command attempts to use a link
  148     Australia/Canberra that does not exist until after the second
  149     command is executed.  Previously, zic had unspecified behavior if
  150     a Link line's target was another link, and zic often misbehaved if
  151     a Link line's target was a later Link line.
  152 
  153     Fix line number in zic's diagnostic for a link to a link.
  154 
  155     Fix a bug that caused localtime to mishandle timestamps starting
  156     in the year 2438 when reading data generated by 'zic -b fat' when
  157     distant-future DST transitions occur at times given in standard
  158     time or in UT, not the usual case of local time.  This occurs when
  159     the corresponding .zi Rule lines specify DST transitions with TO
  160     columns of 'max' and AT columns that end in 's' or 'u'.  The
  161     number 2438 comes from the 32-bit limit in the year 2038, plus the
  162     400-year Gregorian cycle.  (Problem reported by Bradley White.)
  163 
  164     On glibc 2.34 and later, which optionally supports 64-bit time_t
  165     on platforms like x86 where time_t was traditionally 32 bits,
  166     default time_t to 64 instead of 32 bits.  This lets functions like
  167     localtime support timestamps after the year 2038, and fixes
  168     year-2038 problems in zic when accessing files dated after 2038.
  169     To continue to limit time_t to 32 bits on these platforms, use
  170     "make CFLAGS='-D_TIME_BITS=32'".
  171 
  172     In C code, do not enable large-file support on platforms like AIX
  173     and macOS that no longer need it now that tzcode does not use
  174     off_t or related functions like 'stat'.  Large-file support is
  175     still enabled by default on GNU/Linux, as it is needed for 64-bit
  176     time_t support.
  177 
  178     In C code, prefer C23 keywords to pre-C23 macros for alignof,
  179     bool, false, and true.  Also, use the following C23 features if
  180     available: __has_include, unreachable.
  181 
  182     zic no longer works around Qt bug 53071, as the relevant Qt
  183     releases have been out of support since 2019.  This change affects
  184     only fat TZif files, as thin files never had the workaround.
  185 
  186     zdump no longer modifies the environ vector when compiled on
  187     platforms lacking tm_zone or when compiled with -DUSE_LTZ=0.
  188     This avoid undefined behavior on POSIX platforms.
  189 
  190 
  191 Release 2022e - 2022-10-11 11:13:02 -0700
  192 
  193   Briefly:
  194     Jordan and Syria switch from +02/+03 with DST to year-round +03.
  195 
  196   Changes to future timestamps
  197 
  198     Jordan and Syria are abandoning the DST regime and are changing to
  199     permanent +03, so they will not fall back from +03 to +02 on
  200     2022-10-28.  (Thanks to Steffen Thorsen and Issam Al-Zuwairi.)
  201 
  202   Changes to past timestamps
  203 
  204     On 1922-01-01 Tijuana adopted standard time at 00:00, not 01:00.
  205 
  206   Changes to past time zone abbreviations and DST flags
  207 
  208     The temporary advancement of clocks in central Mexico in summer
  209     1931 is now treated as daylight saving time, instead of as two
  210     changes to standard time.
  211 
  212 
  213 Release 2022d - 2022-09-23 12:02:57 -0700
  214 
  215   Briefly:
  216     Palestine transitions are now Saturdays at 02:00.
  217     Simplify three Ukraine zones into one.
  218 
  219   Changes to future timestamps
  220 
  221     Palestine now springs forward and falls back at 02:00 on the
  222     first Saturday on or after March 24 and October 24, respectively.
  223     This means 2022 falls back 10-29 at 02:00, not 10-28 at 01:00.
  224     (Thanks to Heba Hamad.)
  225 
  226   Changes to past timestamps
  227 
  228     Simplify three Ukraine zones to one, since the post-1970
  229     differences seem to have been imaginary.  Move Europe/Uzhgorod and
  230     Europe/Zaporozhye to 'backzone'; backward-compatibility links
  231     still work, albeit with different timestamps before October 1991.
  232 
  233 
  234 Release 2022c - 2022-08-15 17:47:18 -0700
  235 
  236   Briefly:
  237     Work around awk bug in FreeBSD, macOS, etc.
  238     Improve tzselect on intercontinental Zones.
  239 
  240   Changes to code
  241 
  242     Work around a bug in onetrueawk that broke commands like
  243     'make traditional_tarballs' on FreeBSD, macOS, etc.
  244     (Problem reported by Deborah Goldsmith.)
  245 
  246     Add code to tzselect that uses experimental structured comments in
  247     zone1970.tab to clarify whether Zones like Africa/Abidjan and
  248     Europe/Istanbul cross continent or ocean boundaries.
  249     (Inspired by a problem reported by Peter Krefting.)
  250 
  251     Fix bug with 'zic -d /a/b/c' when /a is unwritable but the
  252     directory /a/b already exists.
  253 
  254     Remove zoneinfo2tdf.pl, as it was unused and triggered false
  255     malware alarms on some email servers.
  256 
  257 
  258 Release 2022b - 2022-08-10 15:38:32 -0700
  259 
  260   Briefly:
  261     Chile's DST is delayed by a week in September 2022.
  262     Iran no longer observes DST after 2022.
  263     Rename Europe/Kiev to Europe/Kyiv.
  264     New zic -R option
  265     Vanguard form now uses %z.
  266     Finish moving duplicate-since-1970 zones to 'backzone'.
  267     New build option PACKRATLIST
  268     New tailored_tarballs target, replacing rearguard_tarballs
  269 
  270   Changes to future timestamps
  271 
  272     Chile's 2022 DST start is delayed from September 4 to September 11.
  273     (Thanks to Juan Correa.)
  274 
  275     Iran plans to stop observing DST permanently, after it falls back
  276     on 2022-09-21.  (Thanks to Ali Mirjamali.)
  277 
  278   Changes to past timestamps
  279 
  280     Finish moving to 'backzone' the location-based zones whose
  281     timestamps since 1970 are duplicates; adjust links accordingly.
  282     This change ordinarily affects only pre-1970 timestamps, and with
  283     the new PACKRATLIST option it does not affect any timestamps.
  284     In this round the affected zones are Antarctica/Vostok,
  285     Asia/Brunei, Asia/Kuala_Lumpur, Atlantic/Reykjavik,
  286     Europe/Amsterdam, Europe/Copenhagen, Europe/Luxembourg,
  287     Europe/Monaco, Europe/Oslo, Europe/Stockholm, Indian/Christmas,
  288     Indian/Cocos, Indian/Kerguelen, Indian/Mahe, Indian/Reunion,
  289     Pacific/Chuuk, Pacific/Funafuti, Pacific/Majuro, Pacific/Pohnpei,
  290     Pacific/Wake and Pacific/Wallis, and the affected links are
  291     Arctic/Longyearbyen, Atlantic/Jan_Mayen, Iceland, Pacific/Ponape,
  292     Pacific/Truk, and Pacific/Yap.
  293 
  294     From fall 1994 through fall 1995, Shanks wrote that Crimea's
  295     DST transitions were at 02:00 standard time, not at 00:00.
  296     (Thanks to Michael Deckers.)
  297 
  298     Iran adopted standard time in 1935, not 1946.  In 1977 it observed
  299     DST from 03-21 23:00 to 10-20 24:00; its 1978 transitions were on
  300     03-24 and 08-05, not 03-20 and 10-20; and its spring 1979
  301     transition was on 05-27, not 03-21.
  302     (Thanks to Roozbeh Pournader and Francis Santoni.)
  303 
  304     Chile's observance of -04 from 1946-08-29 through 1947-03-31 was
  305     considered DST, not standard time.  Santiago and environs had moved
  306     their clocks back to rejoin the rest of mainland Chile; put this
  307     change at the end of 1946-08-28.  (Thanks to Michael Deckers.)
  308 
  309     Some old, small clock transitions have been removed, as people at
  310     the time did not change their clocks.  This affects Asia/Hong_Kong
  311     in 1904, Asia/Ho_Chi_Minh in 1906, and Europe/Dublin in 1880.
  312 
  313   Changes to zone name
  314 
  315     Rename Europe/Kiev to Europe/Kyiv, as "Kyiv" is more common in
  316     English now.  Spelling of other names in Ukraine has not yet
  317     demonstrably changed in common English practice so for now these
  318     names retain old spellings, as in other countries (e.g.,
  319     Europe/Prague not "Praha", and Europe/Sofia not "Sofiya").
  320 
  321   Changes to code
  322 
  323     zic has a new option '-R @N' to output explicit transitions < N.
  324     (Need suggested by Almaz Mingaleev.)
  325 
  326     'zic -r @N' no longer outputs bad data when N < first transition.
  327     (Problem introduced in 2021d and reported by Peter Krefting.)
  328 
  329     zic now checks its input for NUL bytes and unterminated lines, and
  330     now supports input line lengths up to 2048 (not 512) bytes.
  331 
  332     gmtime and related code now use the abbreviation "UTC" not "GMT".
  333     POSIX is being revised to require this.
  334 
  335     When tzset and related functions set vestigial static variables
  336     like tzname, they now prefer specified timestamps to unspecified ones.
  337     (Problem reported by Almaz Mingaleev.)
  338 
  339     zic no longer complains "can't determine time zone abbreviation to
  340     use just after until time" when a transition to a new standard
  341     time occurs simultaneously with the first DST fallback transition.
  342 
  343   Changes to build procedure
  344 
  345     Source data in vanguard form now uses the %z notation, introduced
  346     in release 2015f.  For example, for America/Sao_Paulo vanguard
  347     form contains the zone continuation line "-3:00 Brazil %z", which
  348     is simpler and more reliable than the line "-3:00 Brazil -03/-02"
  349     used in main and rearguard forms.  The plan is for the main form
  350     to use %z eventually; in the meantime maintainers of zi parsers
  351     are encouraged to test the parsers on vanguard.zi.
  352 
  353     The Makefile has a new PACKRATLIST option to select a subset of
  354     'backzone'.  For example, 'make PACKRATDATA=backzone
  355     PACKRATLIST=zone.tab' now generates TZif files identical to those
  356     of the global-tz project.
  357 
  358     The Makefile has a new tailored_tarballs target for generating
  359     special-purpose tarballs.  It generalizes and replaces the
  360     rearguard_tarballs target and related targets and macros, which
  361     are now obsolescent.
  362 
  363     'make install' now defaults LOCALTIME to Factory not GMT,
  364     which means the default abbreviation is now "-00" not "GMT".
  365 
  366     Remove the posix_packrat target, marked obsolescent in 2016a.
  367 
  368 
  369 Release 2022a - 2022-03-15 23:02:01 -0700
  370 
  371   Briefly:
  372     Palestine will spring forward on 2022-03-27, not -03-26.
  373     zdump -v now outputs better failure indications.
  374     Bug fixes for code that reads corrupted TZif data.
  375 
  376   Changes to future timestamps
  377 
  378     Palestine will spring forward on 2022-03-27, not 2022-03-26.
  379     (Thanks to Heba Hamad.)  Predict future transitions for first
  380     Sunday >= March 25.  Additionally, predict fallbacks to be the first
  381     Friday on or after October 23, not October's last Friday, to be more
  382     consistent with recent practice.  The first differing fallback
  383     prediction is on 2025-10-24, not 2025-10-31.
  384 
  385   Changes to past timestamps
  386 
  387     From 1992 through spring 1996, Ukraine's DST transitions were at
  388     02:00 standard time, not at 01:00 UTC.  (Thanks to Alois Treindl.)
  389 
  390     Chile's Santiago Mean Time and its LMT precursor have been adjusted
  391     eastward by 1 second to align with past and present law.
  392 
  393   Changes to commentary
  394 
  395     Add several references for Chile's 1946/1947 transitions, some of
  396     which only affected portions of the country.
  397 
  398   Changes to code
  399 
  400     Fix bug when mktime gets confused by truncated TZif files with
  401     unspecified local time.  (Problem reported by Almaz Mingaleev.)
  402 
  403     Fix bug when 32-bit time_t code reads malformed 64-bit TZif data.
  404     (Problem reported by Christos Zoulas.)
  405 
  406     When reading a version 2 or later TZif file, the TZif reader now
  407     validates the version 1 header and data block only enough to skip
  408     over them, as recommended by RFC 8536 section 4.  Also, the TZif
  409     reader no longer mistakenly attempts to parse a version 1 TZIf
  410     file header as a TZ string.
  411 
  412     zdump -v now outputs "(localtime failed)" and "(gmtime failed)"
  413     when local time and UT cannot be determined for a timestamp.
  414 
  415   Changes to build procedure
  416 
  417     Distribution tarballs now use standard POSIX.1-1988 ustar format
  418     instead of GNU format.  Although the formats are almost identical
  419     for these tarballs, ustar headers' magic fields contain "ustar"
  420     instead of "ustar ", and their version fields contain "00" instead
  421     of " ".  The two formats are planned to diverge more significantly
  422     for tzdb releases after 2242-03-16 12:56:31 UTC, when the ustar
  423     format becomes obsolete and the tarballs switch to pax format, an
  424     extension of ustar.  For details about these formats, please see
  425     "pax - portable archive interchange", IEEE Std 1003.1-2017,
  426     <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13>.
  427 
  428 
  429 Release 2021e - 2021-10-21 18:41:00 -0700
  430 
  431   Changes to future timestamps
  432 
  433     Palestine will fall back 10-29 (not 10-30) at 01:00.
  434     (Thanks to P Chan and Heba Hemad.)
  435 
  436 
  437 Release 2021d - 2021-10-15 13:48:18 -0700
  438 
  439   Briefly:
  440     Fiji suspends DST for the 2021/2022 season.
  441     'zic -r' marks unspecified timestamps with "-00".
  442 
  443   Changes to future timestamps
  444 
  445     Fiji will suspend observance of DST for the 2021/2022 season.
  446     Assume for now that it will return next year.  (Thanks to Jashneel
  447     Kumar and P Chan.)
  448 
  449   Changes to code
  450 
  451     'zic -r' now uses "-00" time zone abbreviations for intervals
  452     with UT offsets that are unspecified due to -r truncation.
  453     This implements a change in draft Internet RFC 8536bis.
  454 
  455 
  456 Release 2021c - 2021-10-01 14:21:49 -0700
  457 
  458   Briefly:
  459     Revert most 2021b changes to 'backward'.
  460     Fix 'zic -b fat' bug in pre-1970 32-bit data.
  461     Fix two Link line typos.
  462     Distribute SECURITY file.
  463 
  464     This release is intended as a bugfix release, to fix compatibility
  465     problems and typos reported since 2021b was released.
  466 
  467   Changes to Link directives
  468 
  469     Revert almost all of 2021b's changes to the 'backward' file,
  470     by moving Link directives back to where they were in 2021a.
  471     Although 'zic' doesn't care which source file contains a Link
  472     directive, some downstream uses ran into trouble with the move.
  473     (Problem reported by Stephen Colebourne for Joda-Time.)
  474 
  475     Fix typo that linked Atlantic/Jan_Mayen to the wrong location
  476     (problem reported by Chris Walton).
  477 
  478     Fix 'backzone' typo that linked America/Virgin to the wrong
  479     location (problem reported by Michael Deckers).
  480 
  481   Changes to code
  482 
  483     Fix a bug in 'zic -b fat' that caused old timestamps to be
  484     mishandled in 32-bit-only readers (problem reported by Daniel
  485     Fischer).
  486 
  487   Changes to documentation
  488 
  489     Distribute the SECURITY file (problem reported by Andreas Radke).
  490 
  491 
  492 Release 2021b - 2021-09-24 16:23:00 -0700
  493 
  494   Briefly:
  495     Jordan now starts DST on February's last Thursday.
  496     Samoa no longer observes DST.
  497     Merge more location-based Zones whose timestamps agree since 1970.
  498     Move some backward-compatibility links to 'backward'.
  499     Rename Pacific/Enderbury to Pacific/Kanton.
  500     Correct many pre-1993 transitions in Malawi, Portugal, etc.
  501     zic now creates each output file or link atomically.
  502     zic -L no longer omits the POSIX TZ string in its output.
  503     zic fixes for truncation and leap second table expiration.
  504     zic now follows POSIX for TZ strings using all-year DST.
  505     Fix some localtime crashes and bugs in obscure cases.
  506     zdump -v now outputs more-useful boundary cases.
  507     tzfile.5 better matches a draft successor to RFC 8536.
  508     A new file SECURITY.
  509 
  510     This release is prompted by recent announcements by Jordan and Samoa.
  511     It incorporates many other changes that had accumulated since 2021a.
  512     However, it omits most proposed changes that merged all Zones
  513     agreeing since 1970, as concerns were raised about doing too many of
  514     these changes at once.  It does keeps some of these changes in the
  515     interest of making tzdb more equitable one step at a time; see
  516     "Merge more location-based Zones" below.
  517 
  518   Changes to future timestamps
  519 
  520     Jordan now starts DST on February's last Thursday.
  521     (Thanks to Steffen Thorsen.)
  522 
  523     Samoa no longer observes DST.  (Thanks to Geoffrey D. Bennett.)
  524 
  525   Changes to zone name
  526 
  527     Rename Pacific/Enderbury to Pacific/Kanton.  When we added
  528     Enderbury in 1993, we did not know that it is uninhabited and that
  529     Kanton (population two dozen) is the only inhabited location in
  530     that timezone.  The old name is now a backward-compatibility link.
  531 
  532   Changes to past timestamps
  533 
  534     Correct many pre-1993 transitions, fixing entries originally
  535     derived from Shanks, Whitman, and Mundell.  The fixes include:
  536       - Barbados: standard time was introduced in 1911, not 1932; and
  537 	DST was observed in 1942-1944
  538       - Cook Islands: In 1899 they switched from east to west of GMT,
  539 	celebrating Christmas for two days.  They (and Niue) switched
  540 	to standard time in 1952, not 1901.
  541       - Guyana: corrected LMT for Georgetown; the introduction of
  542 	standard time in 1911, not 1915; and corrections to 1975 and
  543 	1992 transitions
  544       - Kanton: uninhabited before 1937-08-31
  545       - Niue: only observed -11:20 from 1952 through 1964, then went to
  546         -11 instead of -11:30
  547       - Portugal: DST was observed in 1950
  548       - Tonga: corrected LMT; the introduction of standard time in 1945,
  549         not 1901; and corrections to the transition from +12:20 to +13
  550         in 1961, not 1941
  551     Additional fixes to entries in the 'backzone' file include:
  552       - Enderbury: inhabited only 1860/1885 and 1938-03-06/1942-02-09
  553       - The Gambia: 1933 and 1942 transitions
  554       - Malawi: several 1911 through 1925 transitions
  555       - Sierra Leone: several 1913 through 1941 transitions, and DST
  556 	was NOT observed in 1957 through 1962
  557     (Thanks to P Chan, Michael Deckers, Alexander Krivenyshev and
  558     Alois Treindl.)
  559 
  560     Merge more location-based Zones whose timestamps agree since 1970,
  561     as pre-1970 timestamps are out of scope.  This is part of a
  562     process that has been ongoing since 2013.  This does not affect
  563     post-1970 timestamps, and timezone historians who build with 'make
  564     PACKRATDATA=backzone' should see no changes to pre-1970 timestamps.
  565     When merging, keep the most-populous location's data, and move
  566     data for other locations to 'backzone' with a backward
  567     link in 'backward'.  For example, move America/Creston data to
  568     'backzone' with a link in 'backward' from America/Phoenix because
  569     the two timezones' timestamps agree since 1970; this change
  570     affects some pre-1968 timestamps in America/Creston because
  571     Creston and Phoenix disagreed before 1968.  The affected Zones
  572     are Africa/Accra, America/Atikokan, America/Blanc-Sablon,
  573     America/Creston, America/Curacao, America/Nassau,
  574     America/Port_of_Spain, Antarctica/DumontDUrville, and
  575     Antarctica/Syowa.
  576 
  577   Changes to maintenance procedure
  578 
  579     The new file SECURITY covers how to report security-related bugs.
  580 
  581     Several backward-compatibility links have been moved to the
  582     'backward' file.  These links, which range from Africa/Addis_Ababa
  583     to Pacific/Saipan, are only for compatibility with now-obsolete
  584     guidelines suggesting an entry for every ISO 3166 code.
  585     The intercontinental convenience links Asia/Istanbul and
  586     Europe/Nicosia have also been moved to 'backward'.
  587 
  588   Changes to code
  589 
  590     zic now creates each output file or link atomically,
  591     possibly by creating a temporary file and then renaming it.
  592     This avoids races where a TZ setting would temporarily stop
  593     working while zic was installing a replacement file or link.
  594 
  595     zic -L no longer omits the POSIX TZ string in its output.
  596     Starting with 2020a, zic -L truncated its output according to the
  597     "Expires" directive or "#expires" comment in the leapseconds file.
  598     The resulting TZif files omitted daylight saving transitions after
  599     the leap second table expired, which led to far less-accurate
  600     predictions of times after the expiry.  Although future timestamps
  601     cannot be converted accurately in the presence of leap seconds, it
  602     is more accurate to convert near-future timestamps with a few
  603     seconds error than with an hour error, so zic -L no longer
  604     truncates output in this way.
  605 
  606     Instead, when zic -L is given the "Expires" directive, it now
  607     outputs the expiration by appending a no-change entry to the leap
  608     second table.  Although this should work well with most TZif
  609     readers, it does not conform to Internet RFC 8536 and some pickier
  610     clients (including tzdb 2017c through 2021a) reject it, so
  611     "Expires" directives are currently disabled by default.  To enable
  612     them, set the EXPIRES_LINE Makefile variable.  If a TZif file uses
  613     this new feature it is marked with a new TZif version number 4,
  614     a format intended to be documented in a successor to RFC 8536.
  615 
  616     zic -L LEAPFILE -r @LO no longer generates an invalid TZif file
  617     that omits leap second information for the range LO..B when LO
  618     falls between two leap seconds A and B.  Instead, it generates a
  619     TZif version 4 file that represents the previously-missing
  620     information.
  621 
  622     The TZif reader now allows the leap second table to begin with a
  623     correction other than -1 or +1, and to contain adjacent
  624     transitions with equal corrections.  This supports TZif version 4.
  625 
  626     The TZif reader now lets leap seconds occur less than 28 days
  627     apart.  This supports possible future TZif extensions.
  628 
  629     Fix bug that caused 'localtime' etc. to crash when TZ was
  630     set to a all-year DST string like "EST5EDT4,0/0,J365/25" that does
  631     not conform to POSIX but does conform to Internet RFC 8536.
  632 
  633     Fix another bug that caused 'localtime' etc. to crash when TZ was
  634     set to a POSIX-conforming but unusual TZ string like
  635     "EST5EDT4,0/0,J365/0", where almost all the year is DST.
  636 
  637     Fix yet another bug that caused 'localtime' etc. to mishandle slim
  638     TZif files containing leap seconds after the last explicit
  639     transition in the table, or when handling far-future timestamps
  640     in slim TZif files lacking leap seconds.
  641 
  642     Fix localtime misbehavior involving positive leap seconds.
  643     This change affects only behavior for "right" system time,
  644     which contains leap seconds, and only if the UT offset is
  645     not a multiple of 60 seconds when a positive leap second occurs.
  646     (No such timezone exists in tzdb, luckily.)  Without the fix,
  647     the timestamp was ambiguous during a positive leap second.
  648     With the fix, any seconds occurring after a positive leap second
  649     and within the same localtime minute are counted through 60, not
  650     through 59; their UT offset (tm_gmtoff) is the same as before.
  651     Here is how the fix affects timestamps in a timezone with UT
  652     offset +01:23:45 (5025 seconds) and with a positive leap second at
  653     1972-06-30 23:59:60 UTC (78796800):
  654 
  655 	time_t    without the fix      with the fix
  656 	78796800  1972-07-01 01:23:45  1972-07-01 01:23:45 (leap second)
  657 	78796801  1972-07-01 01:23:45  1972-07-01 01:23:46
  658 	...
  659 	78796815  1972-07-01 01:23:59  1972-07-01 01:23:60
  660 	78796816  1972-07-01 01:24:00  1972-07-01 01:24:00
  661 
  662     Fix an unlikely bug that caused 'localtime' etc. to misbehave if
  663     civil time changes a few seconds before time_t wraps around, when
  664     leap seconds are enabled.
  665 
  666     Fix bug in zic -r; in some cases, the dummy time type after the
  667     last time transition disagreed with the TZ string, contrary to
  668     Internet RFC 8563 section 3.3.
  669 
  670     Fix a bug with 'zic -r @X' when X is a negative leap second that
  671     has a nonnegative correction.  Without the fix, the output file
  672     was truncated so that X appeared to be a positive leap second.
  673     Fix a similar, even-less-likely bug when truncating at a positive
  674     leap second that has a nonpositive correction.
  675 
  676     zic -r now reports an error if given rolling leap seconds, as this
  677     usage has never generally worked and is evidently unused.
  678 
  679     zic now generates a POSIX-conforming TZ string for TZif files
  680     where all-year DST is predicted for the indefinite future.
  681     For example, for all-year Eastern Daylight Time, zic now generates
  682     "XXX3EDT4,0/0,J365/23" where it previously generated
  683     "EST5EDT,0/0,J365/25" or "".  (Thanks to Michael Deckers for
  684     noting the possibility of POSIX conformance.)
  685 
  686     zic.c no longer requires sys/wait.h (thanks to spazmodius for
  687     noting it wasn't needed).
  688 
  689     When reading slim TZif files, zdump no longer mishandles leap
  690     seconds on the rare platforms where time_t counts leap seconds,
  691     fixing a bug introduced in 2014g.
  692 
  693     zdump -v now outputs timestamps at boundaries of what localtime
  694     and gmtime can represent, instead of the less-useful timestamps
  695     one day after the minimum and one day before the maximum.
  696     (Thanks to Arthur David Olson for prototype code, and to Manuela
  697     Friedrich for debugging help.)
  698 
  699     zdump's -c and -t options are now consistently inclusive for the
  700     lower time bound and exclusive for the upper.  Formerly they were
  701     inconsistent.  (Confusion noted by Martin Burnicki.)
  702 
  703   Changes to build procedure
  704 
  705     You can now compile with -DHAVE_MALLOC_ERRNO=0 to port to
  706     non-POSIX hosts where malloc doesn't set errno.
  707     (Problem reported by Jan Engelhardt.)
  708 
  709   Changes to documentation
  710 
  711     tzfile.5 better matches a draft successor to RFC 8536
  712     <https://datatracker.ietf.org/doc/draft-murchison-rfc8536bis/01/>.
  713 
  714 
  715 Release 2021a - 2021-01-24 10:54:57 -0800
  716 
  717   Changes to future timestamps
  718 
  719     South Sudan changes from +03 to +02 on 2021-02-01 at 00:00.
  720     (Thanks to Steffen Thorsen.)
  721 
  722 
  723 Release 2020f - 2020-12-29 00:17:46 -0800
  724 
  725   Change to build procedure
  726 
  727     'make rearguard_tarballs' no longer generates a bad rearguard.zi,
  728     fixing a 2020e bug.  (Problem reported by Deborah Goldsmith.)
  729 
  730 
  731 Release 2020e - 2020-12-22 15:14:34 -0800
  732 
  733   Briefly:
  734     Volgograd switches to Moscow time on 2020-12-27 at 02:00.
  735 
  736   Changes to future timestamps
  737 
  738     Volgograd changes time zone from +04 to +03 on 2020-12-27 at 02:00.
  739     (Thanks to Alexander Krivenyshev and Stepan Golosunov.)
  740 
  741   Changes to past timestamps
  742 
  743     Correct many pre-1986 transitions, fixing entries originally
  744     derived from Shanks.  The fixes include:
  745       - Australia: several 1917 through 1971 transitions
  746       - The Bahamas: several 1941 through 1945 transitions
  747       - Bermuda: several 1917 through 1956 transitions
  748       - Belize: several 1942 through 1968 transitions
  749       - Ghana: several 1915 through 1956 transitions
  750       - Israel and Palestine: several 1940 through 1985 transitions
  751       - Kenya and adjacent: several 1908 through 1960 transitions
  752       - Nigeria and adjacent: correcting LMT in Lagos, and several 1905
  753         through 1919 transitions
  754       - Seychelles: the introduction of standard time in 1907, not 1906
  755       - Vanuatu: DST in 1973-1974, and a corrected 1984 transition
  756     (Thanks to P Chan.)
  757 
  758     Because of the Australia change, Australia/Currie (King Island) is
  759     no longer needed, as it is identical to Australia/Hobart for all
  760     timestamps since 1970 and was therefore created by mistake.
  761     Australia/Currie has been moved to the 'backward' file and its
  762     corrected data moved to the 'backzone' file.
  763 
  764   Changes to past time zone abbreviations and DST flags
  765 
  766     To better match legislation in Turks and Caicos, the 2015 shift to
  767     year-round observance of -04 is now modeled as AST throughout before
  768     returning to Eastern Time with US DST in 2018, rather than as
  769     maintaining EDT until 2015-11-01.  (Thanks to P Chan.)
  770 
  771   Changes to documentation
  772 
  773     The zic man page now documents zic's coalescing of transitions
  774     when a zone falls back just before DST springs forward.
  775 
  776 
  777 Release 2020d - 2020-10-21 11:24:13 -0700
  778 
  779   Briefly:
  780     Palestine ends DST earlier than predicted, on 2020-10-24.
  781 
  782   Changes to past and future timestamps
  783 
  784     Palestine ends DST on 2020-10-24 at 01:00, instead of 2020-10-31
  785     as previously predicted (thanks to Sharef Mustafa.)  Its
  786     2019-10-26 fall-back was at 00:00, not 01:00 (thanks to Steffen
  787     Thorsen.)  Its 2015-10-23 transition was at 01:00 not 00:00, and
  788     its spring 2020 transition was on March 28 at 00:00, not March 27
  789     (thanks to Pierre Cashon.)  This affects Asia/Gaza and
  790     Asia/Hebron.  Assume future spring and fall transitions will be on
  791     the Saturday preceding the last Sunday of March and October,
  792     respectively.
  793 
  794 
  795 Release 2020c - 2020-10-16 11:15:53 -0700
  796 
  797   Briefly:
  798     Fiji starts DST later than usual, on 2020-12-20.
  799 
  800   Changes to future timestamps
  801 
  802     Fiji will start DST on 2020-12-20, instead of 2020-11-08 as
  803     previously predicted.  DST will still end on 2021-01-17.
  804     (Thanks to Raymond Kumar and Alan Mintz.)  Assume for now that
  805     the later-than-usual start date is a one-time departure from the
  806     recent pattern.
  807 
  808   Changes to build procedure
  809 
  810     Rearguard tarballs now contain an empty file pacificnew.
  811     Some older downstream software expects this file to exist.
  812     (Problem reported by Mike Cullinan.)
  813 
  814 
  815 Release 2020b - 2020-10-06 18:35:04 -0700
  816 
  817   Briefly:
  818     Revised predictions for Morocco's changes starting in 2023.
  819     Canada's Yukon changes to -07 on 2020-11-01, not 2020-03-08.
  820     Macquarie Island has stayed in sync with Tasmania since 2011.
  821     Casey, Antarctica is at +08 in winter and +11 in summer.
  822     zic no longer supports -y, nor the TYPE field of Rules.
  823 
  824   Changes to future timestamps
  825 
  826     Morocco's spring-forward after Ramadan is now predicted to occur
  827     no sooner than two days after Ramadan, instead of one day.
  828     (Thanks to Milamber.)  The first altered prediction is for 2023,
  829     now predicted to spring-forward on April 30 instead of April 23.
  830 
  831   Changes to past and future timestamps
  832 
  833    Casey Station, Antarctica has been using +08 in winter and +11 in
  834    summer since 2018.  The most recent transition from +08 to +11 was
  835    2020-10-04 00:01.  Also, Macquarie Island has been staying in
  836    sync with Tasmania since 2011.  (Thanks to Steffen Thorsen.)
  837 
  838   Changes to past and future time zone abbreviations and DST flags
  839 
  840     Canada's Yukon, represented by America/Whitehorse and
  841     America/Dawson, changes its time zone rules from -08/-07 to
  842     permanent -07 on 2020-11-01, not on 2020-03-08 as 2020a had it.
  843     This change affects only the time zone abbreviation (MST vs PDT)
  844     and daylight saving flag for the period between the two dates.
  845     (Thanks to Andrew G. Smith.)
  846 
  847   Changes to past timestamps
  848 
  849     Correct several transitions for Hungary for 1918/1983.
  850     For example, the 1983-09-25 fall-back was at 01:00, not 03:00.
  851     (Thanks to Géza Nyáry.)  Also, the 1890 transition to standard
  852     time was on 11-01, not 10-01 (thanks to Michael Deckers).
  853 
  854     The 1891 French transition was on March 16, not March 15.  The
  855     1911-03-11 French transition was at midnight, not a minute later.
  856     Monaco's transitions were on 1892-06-01 and 1911-03-29, not
  857     1891-03-15 and 1911-03-11.  (Thanks to Michael Deckers.)
  858 
  859   Changes to code
  860 
  861     Support for zic's long-obsolete '-y YEARISTYPE' option has been
  862     removed and, with it, so has support for the TYPE field in Rule
  863     lines, which is now reserved for compatibility with earlier zic.
  864     These features were previously deprecated in release 2015f.
  865     (Thanks to Tim Parenti.)
  866 
  867     zic now defaults to '-b slim' instead of to '-b fat'.
  868 
  869     zic's new '-l -' and '-p -' options uninstall any existing
  870     localtime and posixrules files, respectively.
  871 
  872     The undocumented and ineffective tzsetwall function has been
  873     removed.
  874 
  875   Changes to build procedure
  876 
  877     The Makefile now defaults POSIXRULES to '-', so the posixrules
  878     feature (obsolete as of 2019b) is no longer installed by default.
  879 
  880   Changes to documentation and commentary
  881 
  882     The long-obsolete files pacificnew, systemv, and yearistype.sh have
  883     been removed from the distribution.  (Thanks to Tim Parenti.)
  884 
  885 
  886 Release 2020a - 2020-04-23 16:03:47 -0700
  887 
  888   Briefly:
  889     Morocco springs forward on 2020-05-31, not 2020-05-24.
  890     Canada's Yukon advanced to -07 year-round on 2020-03-08.
  891     America/Nuuk renamed from America/Godthab.
  892     zic now supports expiration dates for leap second lists.
  893 
  894   Changes to future timestamps
  895 
  896     Morocco's second spring-forward transition in 2020 will be May 31,
  897     not May 24 as predicted earlier.  (Thanks to Semlali Naoufal.)
  898     Adjust future-year predictions to use the first Sunday after the
  899     day after Ramadan, not the first Sunday after Ramadan.
  900 
  901     Canada's Yukon, represented by America/Whitehorse and
  902     America/Dawson, advanced to -07 year-round, beginning with its
  903     spring-forward transition on 2020-03-08, and will not fall back on
  904     2020-11-01.  Although a government press release calls this
  905     "permanent Pacific Daylight Saving Time", we prefer MST for
  906     consistency with nearby Dawson Creek, Creston, and Fort Nelson.
  907     (Thanks to Tim Parenti.)
  908 
  909   Changes to past timestamps
  910 
  911     Shanghai observed DST in 1919.  (Thanks to Phake Nick.)
  912 
  913   Changes to timezone identifiers
  914 
  915     To reflect current usage in English better, America/Godthab has
  916     been renamed to America/Nuuk.  A backwards-compatibility link
  917     remains for the old name.
  918 
  919   Changes to code
  920 
  921     localtime.c no longer mishandles timestamps after the last
  922     transition in a TZif file with leap seconds and with daylight
  923     saving time transitions projected into the indefinite future.
  924     For example, with TZ='America/Los_Angeles' with leap seconds,
  925     zdump formerly reported a DST transition on 2038-03-14
  926     from 01:59:32.999... to 02:59:33 instead of the correct transition
  927     from 01:59:59.999... to 03:00:00.
  928 
  929     zic -L now supports an Expires line in the leapseconds file, and
  930     truncates the TZif output accordingly.  This propagates leap
  931     second expiration information into the TZif file, and avoids the
  932     abovementioned localtime.c bug as well as similar bugs present in
  933     many client implementations.  If no Expires line is present, zic
  934     -L instead truncates the TZif output based on the #expires comment
  935     present in leapseconds files distributed by tzdb 2018f and later;
  936     however, this usage is obsolescent.  For now, the distributed
  937     leapseconds file has an Expires line that is commented out, so
  938     that the file can be fed to older versions of zic which ignore the
  939     commented-out line.  Future tzdb distributions are planned to
  940     contain a leapseconds file with an Expires line.
  941 
  942     The configuration macros HAVE_TZNAME and USG_COMPAT should now be
  943     set to 1 if the system library supports the feature, and 2 if not.
  944     As before, these macros are nonzero if tzcode should support the
  945     feature, zero otherwise.
  946 
  947     The configuration macro ALTZONE now has the same values with the
  948     same meaning as HAVE_TZNAME and USG_COMPAT.
  949 
  950     The code's defense against CRLF in leap-seconds.list is now
  951     portable to POSIX awk.  (Problem reported by Deborah Goldsmith.)
  952 
  953     Although the undocumented tzsetwall function is not changed in
  954     this release, it is now deprecated in preparation for removal in
  955     future releases.  Due to POSIX requirements, tzsetwall has not
  956     worked for some time.  Any code that uses it should instead use
  957     tzalloc(NULL) or, if portability trumps thread-safety, should
  958     unset the TZ environment variable.
  959 
  960   Changes to commentary
  961 
  962     The Îles-de-la-Madeleine and the Listuguj reserve are noted as
  963     following America/Halifax, and comments about Yukon's "south" and
  964     "north" have been corrected to say "east" and "west".  (Thanks to
  965     Jeffery Nichols.)
  966 
  967 
  968 Release 2019c - 2019-09-11 08:59:48 -0700
  969 
  970   Briefly:
  971     Fiji observes DST from 2019-11-10 to 2020-01-12.
  972     Norfolk Island starts observing Australian-style DST.
  973 
  974   Changes to future timestamps
  975 
  976     Fiji's next DST transitions will be 2019-11-10 and 2020-01-12
  977     instead of 2019-11-03 and 2020-01-19.  (Thanks to Raymond Kumar.)
  978     Adjust future guesses accordingly.
  979 
  980     Norfolk Island will observe Australian-style DST starting in
  981     spring 2019.  The first transition is on 2019-10-06.  (Thanks to
  982     Kyle Czech and Michael Deckers.)
  983 
  984   Changes to past timestamps
  985 
  986     Many corrections to time in Turkey from 1940 through 1985.
  987     (Thanks to Oya Vulaş via Alois Treindl, and to Kıvanç Yazan.)
  988 
  989     The Norfolk Island 1975-03-02 transition was at 02:00 standard
  990     time, not 02:00 DST.  (Thanks to Michael Deckers.)
  991 
  992     South Korea observed DST from 1948 through 1951.  Although this
  993     info was supposed to appear in release 2014j, a typo inadvertently
  994     suppressed the change.  (Thanks to Alois Treindl.)
  995 
  996     Detroit observed DST in 1967 and 1968 following the US DST rules,
  997     except that its 1967 DST began on June 14 at 00:01.  (Thanks to
  998     Alois Treindl for pointing out that the old data entries were
  999     probably wrong.)
 1000 
 1001     Fix several errors in pre-1970 transitions in Perry County, IN.
 1002     (Thanks to Alois Treindl for pointing out the 1967/9 errors.)
 1003 
 1004     Edmonton did not observe DST in 1967 or 1969.  In 1946 Vancouver
 1005     ended DST on 09-29 not 10-13, and Vienna ended DST on 10-07 not
 1006     10-06.  In 1945 Königsberg (now Kaliningrad) switched from +01/+02
 1007     to +02/+03 on 04-10 not 01-01, and its +02/+03 is abbreviated
 1008     EET/EEST, not CET/CEST.  (Thanks to Alois Treindl.)  In 1946
 1009     Königsberg switched to +03 on 04-07 not 01-01.
 1010 
 1011     In 1946 Louisville switched from CST to CDT on 04-28 at 00:01, not
 1012     01-01 at 00:00.  (Thanks to Alois Treindl and Michael Deckers.)
 1013     Also, it switched from CST to CDT on 1950-04-30, not 1947-04-27.
 1014 
 1015     The 1892-05-01 transition in Brussels was at 00:17:30, not at noon.
 1016     (Thanks to Michael Deckers.)
 1017 
 1018   Changes to past time zone abbreviations and DST flags
 1019 
 1020     Hong Kong Winter Time, observed from 1941-10-01 to 1941-12-25,
 1021     is now flagged as DST and is abbreviated HKWT not HKT.
 1022 
 1023   Changes to code
 1024 
 1025     leapseconds.awk now relies only on its input data, rather than
 1026     also relying on its comments.  (Inspired by code from Dennis
 1027     Ferguson and Chris Woodbury.)
 1028 
 1029     The code now defends against CRLFs in leap-seconds.list.
 1030     (Thanks to Brian Inglis and Chris Woodbury.)
 1031 
 1032   Changes to documentation and commentary
 1033 
 1034     theory.html discusses leap seconds.  (Thanks to Steve Summit.)
 1035 
 1036     Nashville's newspapers dueled about the time of day in the 1950s.
 1037     (Thanks to John Seigenthaler.)
 1038 
 1039     Liechtenstein observed Swiss DST in 1941/2.
 1040     (Thanks to Alois Treindl.)
 1041 
 1042 
 1043 Release 2019b - 2019-07-01 00:09:53 -0700
 1044 
 1045   Briefly:
 1046     Brazil no longer observes DST.
 1047     'zic -b slim' outputs smaller TZif files; please try it out.
 1048     Palestine's 2019 spring-forward transition was on 03-29, not 03-30.
 1049 
 1050   Changes to future timestamps
 1051 
 1052     Brazil has canceled DST and will stay on standard time indefinitely.
 1053     (Thanks to Steffen Thorsen, Marcus Diniz, and Daniel Soares de
 1054     Oliveira.)
 1055 
 1056     Predictions for Morocco now go through 2087 instead of 2037, to
 1057     work around a problem on newlib when using TZif files output by
 1058     zic 2019a or earlier.  (Problem reported by David Gauchard.)
 1059 
 1060   Changes to past and future timestamps
 1061 
 1062     Palestine's 2019 spring transition was 03-29 at 00:00, not 03-30
 1063     at 01:00.  (Thanks to Sharef Mustafa and Even Scharning.)  Guess
 1064     future transitions to be March's last Friday at 00:00.
 1065 
 1066   Changes to past timestamps
 1067 
 1068     Hong Kong's 1941-06-15 spring-forward transition was at 03:00, not
 1069     03:30.  Its 1945 transition from JST to HKT was on 11-18 at 02:00,
 1070     not 09-15 at 00:00.  In 1946 its spring-forward transition was on
 1071     04-21 at 00:00, not the previous day at 03:30.  From 1946 through
 1072     1952 its fall-back transitions occurred at 04:30, not at 03:30.
 1073     In 1947 its fall-back transition was on 11-30, not 12-30.
 1074     (Thanks to P Chan.)
 1075 
 1076   Changes to past time zone abbreviations
 1077 
 1078     Italy's 1866 transition to Rome Mean Time was on December 12, not
 1079     September 22.  This affects only the time zone abbreviation for
 1080     Europe/Rome between those dates.  (Thanks to Stephen Trainor and
 1081     Luigi Rosa.)
 1082 
 1083   Changes affecting metadata only
 1084 
 1085     Add info about the Crimea situation in zone1970.tab and zone.tab.
 1086     (Problem reported by Serhii Demediuk.)
 1087 
 1088   Changes to code
 1089 
 1090     zic's new -b option supports a way to control data bloat and to
 1091     test for year-2038 bugs in software that reads TZif files.
 1092     'zic -b fat' and 'zic -b slim' generate larger and smaller output;
 1093     for example, changing from fat to slim shrinks the Europe/London
 1094     file from 3648 to 1599 bytes, saving about 56%.  Fat and slim
 1095     files represent the same set of timestamps and use the same TZif
 1096     format as documented in tzfile(5) and in Internet RFC 8536.
 1097     Fat format attempts to work around bugs or incompatibilities in
 1098     older software, notably software that mishandles 64-bit TZif data
 1099     or uses obsolete TZ strings like "EET-2EEST" that lack DST rules.
 1100     Slim format is more efficient and does not work around 64-bit bugs
 1101     or obsolete TZ strings.  Currently zic defaults to fat format
 1102     unless you compile with -DZIC_BLOAT_DEFAULT=\"slim\"; this
 1103     out-of-the-box default is intended to change in future releases
 1104     as the buggy software often mishandles timestamps anyway.
 1105 
 1106     zic no longer treats a set of rules ending in 2037 specially.
 1107     Previously, zic assumed that such a ruleset meant that future
 1108     timestamps could not be predicted, and therefore omitted a
 1109     POSIX-like TZ string in the TZif output.  The old behavior is no
 1110     longer needed for current tzdata, and caused problems with newlib
 1111     when used with older tzdata (reported by David Gauchard).
 1112 
 1113     zic no longer generates some artifact transitions.  For example,
 1114     Europe/London no longer has a no-op transition in January 1996.
 1115 
 1116   Changes to build procedure
 1117 
 1118     tzdata.zi now assumes zic 2017c or later.  This shrinks tzdata.zi
 1119     by a percent or so.
 1120 
 1121   Changes to documentation and commentary
 1122 
 1123     The Makefile now documents the POSIXRULES macro as being obsolete,
 1124     and similarly, zic's -p POSIXRULES option is now documented as
 1125     being obsolete.  Although the POSIXRULES feature still exists and
 1126     works as before, in practice it is rarely used for its intended
 1127     purpose, and it does not work either in the default reference
 1128     implementation (for timestamps after 2037) or in common
 1129     implementations such as GNU/Linux (for contemporary timestamps).
 1130     Since POSIXRULES was designed primarily as a temporary transition
 1131     facility for System V platforms that died off decades ago, it is
 1132     being decommissioned rather than institutionalized.
 1133 
 1134     New info on Bonin Islands and Marcus (thanks to Wakaba and Phake Nick).
 1135 
 1136 
 1137 Release 2019a - 2019-03-25 22:01:33 -0700
 1138 
 1139   Briefly:
 1140     Palestine "springs forward" on 2019-03-30 instead of 2019-03-23.
 1141     Metlakatla "fell back" to rejoin Alaska Time on 2019-01-20 at 02:00.
 1142 
 1143   Changes to past and future timestamps
 1144 
 1145     Palestine will not start DST until 2019-03-30, instead of 2019-03-23 as
 1146     previously predicted.  Adjust our prediction by guessing that spring
 1147     transitions will be between 24 and 30 March, which matches recent practice
 1148     since 2016.  (Thanks to Even Scharning and Tim Parenti.)
 1149 
 1150     Metlakatla ended its observance of Pacific standard time,
 1151     rejoining Alaska Time, on 2019-01-20 at 02:00.  (Thanks to Ryan
 1152     Stanley and Tim Parenti.)
 1153 
 1154   Changes to past timestamps
 1155 
 1156     Israel observed DST in 1980 (08-02/09-13) and 1984 (05-05/08-25).
 1157     (Thanks to Alois Treindl and Isaac Starkman.)
 1158 
 1159   Changes to time zone abbreviations
 1160 
 1161     Etc/UCT is now a backward-compatibility link to Etc/UTC, instead
 1162     of being a separate zone that generates the abbreviation "UCT",
 1163     which nowadays is typically a typo.  (Problem reported by Isiah
 1164     Meadows.)
 1165 
 1166   Changes to code
 1167 
 1168     zic now has an -r option to limit the time range of output data.
 1169     For example, 'zic -r @1000000000' limits the output data to
 1170     timestamps starting 1000000000 seconds after the Epoch.
 1171     This helps shrink output size and can be useful for applications
 1172     not needing the full timestamp history, such as TZDIST truncation;
 1173     see Internet RFC 8536 section 5.1.  (Inspired by a feature request
 1174     from Christopher Wong, helped along by bug reports from Wong and
 1175     from Tim Parenti.)
 1176 
 1177   Changes to documentation
 1178 
 1179     Mention Internet RFC 8536 (February 2019), which documents TZif.
 1180 
 1181     tz-link.html now cites tzdata-meta
 1182     <https://tzdata-meta.timtimeonline.com/>.
 1183 
 1184 
 1185 Release 2018i - 2018-12-30 11:05:43 -0800
 1186 
 1187   Briefly:
 1188     São Tomé and Príncipe switches from +01 to +00 on 2019-01-01.
 1189 
 1190   Changes to future timestamps
 1191 
 1192     Due to a change in government, São Tomé and Príncipe switches back
 1193     from +01 to +00 on 2019-01-01 at 02:00.  (Thanks to Vadim
 1194     Nasardinov and Michael Deckers.)
 1195 
 1196 
 1197 Release 2018h - 2018-12-23 17:59:32 -0800
 1198 
 1199   Briefly:
 1200     Qyzylorda, Kazakhstan moved from +06 to +05 on 2018-12-21.
 1201     New zone Asia/Qostanay because Qostanay, Kazakhstan didn't move.
 1202     Metlakatla, Alaska observes PST this winter only.
 1203     Guess Morocco will continue to adjust clocks around Ramadan.
 1204     Add predictions for Iran from 2038 through 2090.
 1205 
 1206   Changes to future timestamps
 1207 
 1208     Guess that Morocco will continue to fall back just before and
 1209     spring forward just after Ramadan, the practice since 2012.
 1210     (Thanks to Maamar Abdelkader.)  This means Morocco will observe
 1211     negative DST during Ramadan in main and vanguard formats, and in
 1212     rearguard format it stays in the +00 timezone and observes
 1213     ordinary DST in all months other than Ramadan.  As before, extend
 1214     this guesswork to the year 2037.  As a consequence, Morocco is
 1215     scheduled to observe three DST transitions in some Gregorian years
 1216     (e.g., 2033) due to the mismatch between the Gregorian and Islamic
 1217     calendars.
 1218 
 1219     The table of exact transitions for Iranian DST has been extended.
 1220     It formerly cut off before the year 2038 in a nod to 32-bit time_t.
 1221     It now cuts off before 2091 as there is doubt about how the Persian
 1222     calendar will treat 2091.  This change predicts DST transitions in
 1223     2038-9, 2042-3, and 2046-7 to occur one day later than previously
 1224     predicted.  As before, post-cutoff transitions are approximated.
 1225 
 1226   Changes to past and future timestamps
 1227 
 1228     Qyzylorda (aka Kyzylorda) oblast in Kazakhstan moved from +06 to
 1229     +05 on 2018-12-21.  This is a zone split as Qostanay (aka
 1230     Kostanay) did not switch, so create a zone Asia/Qostanay.
 1231 
 1232     Metlakatla moved from Alaska to Pacific standard time on 2018-11-04.
 1233     It did not change clocks that day and remains on -08 this winter.
 1234     (Thanks to Ryan Stanley.)  It will revert to the usual Alaska
 1235     rules next spring, so this change affects only timestamps
 1236     from 2018-11-04 through 2019-03-10.
 1237 
 1238   Change to past timestamps
 1239 
 1240     Kwajalein's 1993-08-20 transition from -12 to +12 was at 24:00,
 1241     not 00:00.  I transcribed the time incorrectly from Shanks.
 1242     (Thanks to Phake Nick.)
 1243 
 1244     Nauru's 1979 transition was on 02-10 at 02:00, not 05-01 at 00:00.
 1245     (Thanks to Phake Nick.)
 1246 
 1247     Guam observed DST irregularly from 1959 through 1977.
 1248     (Thanks to Phake Nick.)
 1249 
 1250     Hong Kong observed DST in 1941 starting 06-15 (not 04-01), then on
 1251     10-01 changed standard time to +08:30 (not +08).  Its transition
 1252     back to +08 after WWII was on 1945-09-15, not the previous day.
 1253     Its 1904-10-30 change took effect at 01:00 +08 (not 00:00 LMT).
 1254     (Thanks to Phake Nick, Steve Allen, and Joseph Myers.)  Also,
 1255     its 1952 fallback was on 11-02 (not 10-25).
 1256 
 1257     This release contains many changes to timestamps before 1946 due
 1258     to Japanese possession or occupation of Pacific/Chuuk,
 1259     Pacific/Guam, Pacific/Kosrae, Pacific/Kwajalein, Pacific/Majuro,
 1260     Pacific/Nauru, Pacific/Palau, and Pacific/Pohnpei.
 1261     (Thanks to Phake Nick.)
 1262 
 1263     Assume that the Spanish East Indies was like the Philippines and
 1264     observed American time until the end of 1844.  This affects
 1265     Pacific/Chuuk, Pacific/Kosrae, Pacific/Palau, and Pacific/Pohnpei.
 1266 
 1267   Changes to past tm_isdst flags
 1268 
 1269     For the recent Morocco change, the tm_isdst flag should be 1 from
 1270     2018-10-27 00:00 to 2018-10-28 03:00.  (Thanks to Michael Deckers.)
 1271     Give a URL to the official decree.  (Thanks to Matt Johnson.)
 1272 
 1273 
 1274 Release 2018g - 2018-10-26 22:22:45 -0700
 1275 
 1276   Briefly:
 1277     Morocco switches to permanent +01 on 2018-10-28.
 1278 
 1279   Changes to future timestamps
 1280 
 1281     Morocco switches from +00/+01 to permanent +01 effective 2018-10-28,
 1282     so its clocks will not fall back as previously scheduled.
 1283     (Thanks to Mohamed Essedik Najd and Brian Inglis.)
 1284 
 1285   Changes to code
 1286 
 1287     When generating TZif files with leap seconds, zic no longer uses a
 1288     format that trips up older 32-bit clients, fixing a bug introduced
 1289     in 2018f.  (Reported by Daniel Fischer.)  Also, the zic workaround
 1290     for QTBUG-53071 now also works for TZif files with leap seconds.
 1291 
 1292     The translator to rearguard format now rewrites the line
 1293     "Rule Japan 1948 1951 - Sep Sat>=8 25:00 0 S" to
 1294     "Rule Japan 1948 1951 - Sep Sun>=9  1:00 0 S".
 1295     This caters to zic before 2007 and to Oracle TZUpdater 2.2.0
 1296     and earlier.  (Reported by Christos Zoulas.)
 1297 
 1298   Changes to past time zone abbreviations
 1299 
 1300     Change HDT to HWT/HPT for WWII-era abbreviations in Hawaii.
 1301     This reverts to 2011h, as the abbreviation change in 2011i was
 1302     likely inadvertent.
 1303 
 1304   Changes to documentation
 1305 
 1306     tzfile.5 has new sections on interoperability issues.
 1307 
 1308 
 1309 Release 2018f - 2018-10-18 00:14:18 -0700
 1310 
 1311   Briefly:
 1312   Volgograd moves from +03 to +04 on 2018-10-28.
 1313   Fiji ends DST 2019-01-13, not 2019-01-20.
 1314   Most of Chile changes DST dates, effective 2019-04-06.
 1315 
 1316   Changes to future timestamps
 1317 
 1318     Volgograd moves from +03 to +04 on 2018-10-28 at 02:00.
 1319     (Thanks to Alexander Fetisov and Stepan Golosunov.)
 1320 
 1321     Fiji ends DST 2019-01-13 instead of the 2019-01-20 previously
 1322     predicted.  (Thanks to Raymond Kumar.)  Adjust future predictions
 1323     accordingly.
 1324 
 1325     Most of Chile will end DST on the first Saturday in April at 24:00 mainland
 1326     time, and resume DST on the first Saturday in September at 24:00 mainland
 1327     time.  The changes are effective from 2019-04-06, and do not affect the
 1328     Magallanes region modeled by America/Punta_Arenas.  (Thanks to Juan Correa
 1329     and Tim Parenti.)  Adjust future predictions accordingly.
 1330 
 1331   Changes to past timestamps
 1332 
 1333     The 2018-05-05 North Korea 30-minute time zone change took place
 1334     at 23:30 the previous day, not at 00:00 that day.
 1335 
 1336     China's 1988 spring-forward transition was on April 17, not
 1337     April 10.  Its DST transitions in 1986/91 were at 02:00, not 00:00.
 1338     (Thanks to P Chan.)
 1339 
 1340     Fix several issues for Macau before 1992.  Macau's pre-1904 LMT
 1341     was off by 10 s.  Macau switched to +08 in 1904 not 1912, and
 1342     temporarily switched to +09/+10 during World War II.  Macau
 1343     observed DST in 1942/79, not 1961/80, and there were several
 1344     errors for transition times and dates.  (Thanks to P Chan.)
 1345 
 1346     The 1948-1951 fallback transitions in Japan were at 25:00 on
 1347     September's second Saturday, not at 24:00.  (Thanks to Phake Nick.)
 1348     zic turns this into 01:00 on the day after September's second
 1349     Saturday, which is the best that POSIX or C platforms can do.
 1350 
 1351     Incorporate 1940-1949 Asia/Shanghai DST transitions from a 2014
 1352     paper by Li Yu, replacing more-questionable data from Shanks.
 1353 
 1354   Changes to time zone abbreviations
 1355 
 1356     Use "PST" and "PDT" for Philippine time.  (Thanks to Paul Goyette.)
 1357 
 1358   Changes to code
 1359 
 1360     zic now always generates TZif files where time type 0 is used for
 1361     timestamps before the first transition.  This simplifies the
 1362     reading of TZif files and should not affect behavior of existing
 1363     TZif readers because the same set of time types is used; only
 1364     their internal indexes may have changed.  This affects only the
 1365     legacy zones EST5EDT, CST6CDT, MST7MDT, PST8PDT, CET, MET, and
 1366     EET, which previously used nonzero types for these timestamps.
 1367 
 1368     Because of the type 0 change, zic no longer outputs a dummy
 1369     transition at time -2**59 (before the Big Bang), as clients should
 1370     no longer need this to handle historical timestamps correctly.
 1371     This reverts a change introduced in 2013d and shrinks most TZif
 1372     files by a few bytes.
 1373 
 1374     zic now supports negative time-of-day in Rule and Leap lines, e.g.,
 1375     "Rule X min max - Apr lastSun -6:00 1:00 -" means the transition
 1376     occurs at 18:00 on the Saturday before the last Sunday in April.
 1377     This behavior was documented in 2018a but the code did not
 1378     entirely match the documentation.
 1379 
 1380     localtime.c no longer requires at least one time type in TZif
 1381     files that lack transitions or have a POSIX-style TZ string.  This
 1382     future-proofs the code against possible future extensions to the
 1383     format that would allow TZif files with POSIX-style TZ strings and
 1384     without transitions or time types.
 1385 
 1386     A read-access subscript error in localtime.c has been fixed.
 1387     It could occur only in TZif files with timecnt == 0, something that
 1388     does not happen in practice now but could happen in future versions.
 1389 
 1390     localtime.c no longer ignores TZif POSIX-style TZ strings that
 1391     specify only standard time.  Instead, these TZ strings now
 1392     override the default time type for timestamps after the last
 1393     transition (or for all timestamps if there are no transitions),
 1394     just as DST strings specifying DST have always done.
 1395 
 1396     leapseconds.awk now outputs "#updated" and "#expires" comments,
 1397     and supports leap seconds at the ends of months other than June
 1398     and December.  (Inspired by suggestions from Chris Woodbury.)
 1399 
 1400   Changes to documentation
 1401 
 1402     New restrictions: A Rule name must start with a character that
 1403     is neither an ASCII digit nor "-" nor "+", and an unquoted name
 1404     should not use characters in the set "!$%&'()*,/:;<=>?@[\]^`{|}~".
 1405     The latter restriction makes room for future extensions (a
 1406     possibility noted by Tom Lane).
 1407 
 1408     tzfile.5 now documents what time types apply before the first and
 1409     after the last transition, if any.
 1410 
 1411     Documentation now uses the spelling "timezone" for a TZ setting
 1412     that determines timestamp history, and "time zone" for a
 1413     geographic region currently sharing the same standard time.
 1414 
 1415     The name "TZif" is now used for the tz binary data format.
 1416 
 1417     tz-link.htm now mentions the A0 TimeZone Migration utilities.
 1418     (Thanks to Aldrin Martoq for the link.)
 1419 
 1420   Changes to build procedure
 1421 
 1422     New 'make' target 'rearguard_tarballs' to build the rearguard
 1423     tarball only.  This is a convenience on platforms that lack lzip
 1424     if you want to build the rearguard tarball.  (Problem reported by
 1425     Deborah Goldsmith.)
 1426 
 1427     tzdata.zi is now more stable from release to release.  (Problem
 1428     noted by Tom Lane.)  It is also a bit shorter.
 1429 
 1430     tzdata.zi now can contain comment lines documenting configuration
 1431     information, such as which data format was selected, which input
 1432     files were used, and how leap seconds are treated.  (Problems
 1433     noted by Lester Caine and Brian Inglis.)  If the Makefile defaults
 1434     are used these comment lines are absent, for backward
 1435     compatibility.  A redistributor intending to alter its copy of the
 1436     files should also append "-LABEL" to the 'version' file's first
 1437     line, where "LABEL" identifies the redistributor's change.
 1438 
 1439 
 1440 Release 2018e - 2018-05-01 23:42:51 -0700
 1441 
 1442   Briefly:
 1443 
 1444     North Korea switches back to +09 on 2018-05-05.
 1445     The main format uses negative DST again, for Ireland etc.
 1446     'make tarballs' now also builds a rearguard tarball.
 1447     New 's' and 'd' suffixes in SAVE columns of Rule and Zone lines.
 1448 
 1449   Changes to past and future timestamps
 1450 
 1451     North Korea switches back from +0830 to +09 on 2018-05-05.
 1452     (Thanks to Kang Seonghoon, Arthur David Olson, Seo Sanghyeon,
 1453     and Tim Parenti.)
 1454 
 1455     Bring back the negative-DST changes of 2018a, except be more
 1456     compatible with data parsers that do not support negative DST.
 1457     Also, this now affects historical timestamps in Namibia and the
 1458     former Czechoslovakia, not just Ireland.  The main format now uses
 1459     negative DST to model timestamps in Europe/Dublin (from 1971 on),
 1460     Europe/Prague (1946/7), and Africa/Windhoek (1994/2017).  This
 1461     does not affect UT offsets, only time zone abbreviations and the
 1462     tm_isdst flag.  Also, this does not affect rearguard or vanguard
 1463     formats; effectively the main format now uses vanguard instead of
 1464     rearguard format.  Data parsers that do not support negative DST
 1465     can still use data from the rearguard tarball described below.
 1466 
 1467   Changes to build procedure
 1468 
 1469     The command 'make tarballs' now also builds the tarball
 1470     tzdataVERSION-rearguard.tar.gz, which is like tzdataVERSION.tar.gz
 1471     except that it uses rearguard format intended for trailing-edge
 1472     data parsers.
 1473 
 1474   Changes to data format and to code
 1475 
 1476     The SAVE column of Rule and Zone lines can now have an 's' or 'd'
 1477     suffix, which specifies whether the adjusted time is standard time
 1478     or daylight saving time.  If no suffix is given, daylight saving
 1479     time is used if and only if the SAVE column is nonzero; this is
 1480     the longstanding behavior.  Although this new feature is not used
 1481     in tzdata, it could be used to specify the legal time in Namibia
 1482     1994-2017, as opposed to the popular time (see below).
 1483 
 1484   Changes to past timestamps
 1485 
 1486     From 1994 through 2017 Namibia observed DST in winter, not summer.
 1487     That is, it used negative DST, as Ireland still does.  This change
 1488     does not affect UTC offsets; it affects only the tm_isdst flag and
 1489     the abbreviation used during summer, which is now CAT, not WAST.
 1490     Although (as noted by Michael Deckers) summer and winter time were
 1491     both simply called "standard time" in Namibian law, in common
 1492     practice winter time was considered to be DST (as noted by Stephen
 1493     Colebourne).  The full effect of this change is only in vanguard
 1494     and main format; in rearguard format, the tm_isdst flag is still
 1495     zero in winter and nonzero in summer.
 1496 
 1497     In 1946/7 Czechoslovakia also observed negative DST in winter.
 1498     The full effect of this change is only in vanguard and main
 1499     formats; in rearguard format, it is modeled as plain GMT without
 1500     daylight saving.  Also, the dates of some 1944/5 DST transitions
 1501     in Czechoslovakia have been changed.
 1502 
 1503 
 1504 Release 2018d - 2018-03-22 07:05:46 -0700
 1505 
 1506   Briefly:
 1507 
 1508   Palestine starts DST a week earlier in 2018.
 1509   Add support for vanguard and rearguard data consumers.
 1510   Add subsecond precision to source data format, though not to data.
 1511 
 1512   Changes to future timestamps
 1513 
 1514     In 2018, Palestine starts DST on March 24, not March 31.
 1515     Adjust future predictions accordingly.  (Thanks to Sharef Mustafa.)
 1516 
 1517   Changes to past and future timestamps
 1518 
 1519     Casey Station in Antarctica changed from +11 to +08 on 2018-03-11
 1520     at 04:00.  (Thanks to Steffen Thorsen.)
 1521 
 1522   Changes to past timestamps
 1523 
 1524     Historical transitions for Uruguay, represented by
 1525     America/Montevideo, have been updated per official legal documents,
 1526     replacing previous data mainly originating from the inventions of
 1527     Shanks & Pottenger.  This has resulted in adjustments ranging from
 1528     30 to 90 minutes in either direction over at least two dozen
 1529     distinct periods ranging from one day to several years in length.
 1530     A mere handful of pre-1991 transitions are unaffected; data since
 1531     then has come from more reliable contemporaneous reporting.  These
 1532     changes affect various timestamps in 1920-1923, 1936, 1939,
 1533     1942-1943, 1959, 1966-1970, 1972, 1974-1980, and 1988-1990.
 1534     Additionally, Uruguay's pre-standard-time UT offset has been
 1535     adjusted westward by 7 seconds, from UT-03:44:44 to UT-03:44:51, to
 1536     match the location of the Observatory of the National Meteorological
 1537     Institute in Montevideo.
 1538     (Thanks to Jeremie Bonjour, Tim Parenti, and Michael Deckers.)
 1539 
 1540     East Kiribati skipped New Year's Eve 1994, not New Year's Day 1995.
 1541     (Thanks to Kerry Shetline.)
 1542 
 1543     Fix the 1912-01-01 transition for Portugal and its colonies.
 1544     This transition was at 00:00 according to the new UT offset, not
 1545     according to the old one.  Also assume that Cape Verde switched on
 1546     the same date as the rest, not in 1907.  This affects
 1547     Africa/Bissau, Africa/Sao_Tome, Asia/Macau, Atlantic/Azores,
 1548     Atlantic/Cape_Verde, Atlantic/Madeira, and Europe/Lisbon.
 1549     (Thanks to Michael Deckers.)
 1550 
 1551     Fix an off-by-1 error for pre-1913 timestamps in Jamaica and in
 1552     Turks & Caicos.
 1553 
 1554   Changes to past time zone abbreviations
 1555 
 1556     MMT took effect in Uruguay from 1908-06-10, not 1898-06-28.  There
 1557     is no clock change associated with the transition.
 1558 
 1559   Changes to build procedure
 1560 
 1561     The new DATAFORM macro in the Makefile lets the installer choose
 1562     among three source data formats.  The idea is to lessen downstream
 1563     disruption when data formats are improved.
 1564 
 1565     * DATAFORM=vanguard installs from the latest, bleeding-edge
 1566       format.  DATAFORM=main (the default) installs from the format
 1567       used in the 'africa' etc. files.  DATAFORM=rearguard installs
 1568       from a trailing-edge format.  Eventually, elements of today's
 1569       vanguard format should move to the main format, and similarly
 1570       the main format's features should eventually move to the
 1571       rearguard format.
 1572 
 1573     * In the current version, the main and rearguard formats are
 1574       identical and match that of 2018c, so this change does not
 1575       affect default behavior.  The vanguard format currently contains
 1576       one feature not in the main format: negative SAVE values.  This
 1577       improves support for Ireland, which uses Irish Standard Time
 1578       (IST, UTC+01) in summer and GMT (UTC) in winter.  tzcode has
 1579       supported negative SAVE values for decades, and this feature
 1580       should move to the main format soon.  However, it will not move
 1581       to the rearguard format for quite some time because some
 1582       downstream parsers do not support it.
 1583 
 1584     * The build procedure constructs three files vanguard.zi, main.zi,
 1585       and rearguard.zi, one for each format.  Although the files
 1586       represent essentially the same data, they may have minor
 1587       discrepancies that users are not likely to notice.  The files
 1588       are intended for downstream data consumers and are not
 1589       installed.  Zoneinfo parsers that do not support negative SAVE values
 1590       should start using rearguard.zi, so that they will be unaffected
 1591       when the negative-DST feature moves from vanguard to main.
 1592       Bleeding-edge Zoneinfo parsers that support the new features
 1593       already can use vanguard.zi; in this respect, current tzcode is
 1594       bleeding-edge.
 1595 
 1596     The Makefile should now be safe for parallelized builds, and 'make
 1597     -j to2050new.tzs' is now much faster on a multiprocessor host
 1598     with GNU Make.
 1599 
 1600     When built with -DSUPPRESS_TZDIR, the tzcode library no longer
 1601     prepends TZDIR/ to file names that do not begin with '/'.  This is
 1602     not recommended for general use, due to its security implications.
 1603     (From a suggestion by Manuela Friedrich.)
 1604 
 1605   Changes to code
 1606 
 1607     zic now accepts subsecond precision in expressions like
 1608     00:19:32.13, which is approximately the legal time of the
 1609     Netherlands from 1835 to 1937.  However, because it is
 1610     questionable whether the few recorded uses of non-integer offsets
 1611     had subsecond precision in practice, there are no plans for tzdata
 1612     to use this feature.  (Thanks to Steve Allen for pointing out
 1613     the limitations of historical data in this area.)
 1614 
 1615     The code is a bit more portable to MS-Windows.  Installers can
 1616     compile with -DRESERVE_STD_EXT_IDS on MS-Windows platforms that
 1617     reserve identifiers like 'localtime'.  (Thanks to Manuela
 1618     Friedrich.)
 1619 
 1620   Changes to documentation and commentary
 1621 
 1622     theory.html now outlines tzdb's extensions to POSIX's model for
 1623     civil time, and has a section "POSIX features no longer needed"
 1624     that lists POSIX API components that are now vestigial.
 1625     (From suggestions by Steve Summit.)  It also better distinguishes
 1626     time zones from tz regions.  (From a suggestion by Guy Harris.)
 1627 
 1628     Commentary is now more consistent about using the phrase "daylight
 1629     saving time", to match the C name tm_isdst.  Daylight saving time
 1630     need not occur in summer, and need not have a positive offset from
 1631     standard time.
 1632 
 1633     Commentary about historical transitions in Uruguay has been expanded
 1634     with links to many relevant legal documents.
 1635     (Thanks to Tim Parenti.)
 1636 
 1637     Commentary now uses some non-ASCII characters with Unicode value
 1638     less than U+0100, as they can be useful and should work even with
 1639     older editors such as XEmacs.
 1640 
 1641 
 1642 Release 2018c - 2018-01-22 23:00:44 -0800
 1643 
 1644   Briefly:
 1645   Revert Irish changes that relied on negative SAVE values.
 1646 
 1647   Changes to tm_isdst
 1648 
 1649     Revert the 2018a change to Europe/Dublin.  As before, this change
 1650     does not affect UT offsets or abbreviations; it affects only
 1651     whether timestamps are considered to be standard time or
 1652     daylight-saving time, as expressed in the tm_isdst flag of C's
 1653     struct tm type.  This reversion is intended to be a temporary
 1654     workaround for problems discovered with downstream uses of
 1655     releases 2018a and 2018b, which implemented Irish time by using
 1656     negative SAVE values in the Eire rules of the 'europe' file.
 1657     Although negative SAVE values have been part of tzcode for many
 1658     years and are supported by many platforms, they were not
 1659     documented before 2018a and ICU and OpenJDK do not currently
 1660     support them.  A mechanism to export data to platforms lacking
 1661     support for negative DST is planned to be developed before the
 1662     change is reapplied.  (Problems reported by Deborah Goldsmith and
 1663     Stephen Colebourne.)
 1664 
 1665   Changes to past timestamps
 1666 
 1667     Japanese DST transitions (1948-1951) were Sundays at 00:00, not
 1668     Saturdays or Sundays at 02:00.  (Thanks to Takayuki Nikai.)
 1669 
 1670   Changes to build procedure
 1671 
 1672     The build procedure now works around mawk 1.3.3's lack of support
 1673     for character class expressions.  (Problem reported by Ohyama.)
 1674 
 1675 
 1676 Release 2018b - 2018-01-17 23:24:48 -0800
 1677 
 1678   Briefly:
 1679   Fix a packaging problem in tz2018a, which was missing 'pacificnew'.
 1680 
 1681   Changes to build procedure
 1682 
 1683     The distribution now contains the file 'pacificnew' again.
 1684     This file was inadvertently omitted in the 2018a distribution.
 1685     (Problem reported by Matias Fonzo.)
 1686 
 1687 
 1688 Release 2018a - 2018-01-12 22:29:21 -0800
 1689 
 1690   Briefly:
 1691   São Tomé and Príncipe switched from +00 to +01.
 1692   Brazil's DST will now start on November's first Sunday.
 1693   Ireland's standard time is now in the summer, not the winter.
 1694   Use Debian-style installation locations, instead of 4.3BSD-style.
 1695   New zic option -t.
 1696 
 1697   Changes to past and future timestamps
 1698 
 1699     São Tomé and Príncipe switched from +00 to +01 on 2018-01-01 at
 1700     01:00.  (Thanks to Steffen Thorsen and Michael Deckers.)
 1701 
 1702   Changes to future timestamps
 1703 
 1704     Starting in 2018 southern Brazil will begin DST on November's
 1705     first Sunday instead of October's third Sunday.  (Thanks to
 1706     Steffen Thorsen.)
 1707 
 1708   Changes to past timestamps
 1709 
 1710     A discrepancy of 4 s in timestamps before 1931 in South Sudan has
 1711     been corrected.  The 'backzone' and 'zone.tab' files did not agree
 1712     with the 'africa' and 'zone1970.tab' files.  (Problem reported by
 1713     Michael Deckers.)
 1714 
 1715     The abbreviation invented for Bolivia Summer Time (1931-2) is now
 1716     BST instead of BOST, to be more consistent with the convention
 1717     used for Latvian Summer Time (1918-9) and for British Summer Time.
 1718 
 1719   Changes to tm_isdst
 1720 
 1721     Change Europe/Dublin so that it observes Irish Standard Time (UT
 1722     +01) in summer and GMT (as negative daylight-saving) in winter,
 1723     instead of observing standard time (GMT) in winter and Irish
 1724     Summer Time (UT +01) in summer.  This change does not affect UT
 1725     offsets or abbreviations; it affects only whether timestamps are
 1726     considered to be standard time or daylight-saving time, as
 1727     expressed in the tm_isdst flag of C's struct tm type.
 1728     (Discrepancy noted by Derick Rethans.)
 1729 
 1730   Changes to build procedure
 1731 
 1732     The default installation locations have been changed to mostly
 1733     match Debian circa 2017, instead of being designed as an add-on to
 1734     4.3BSD circa 1986.  This affects the Makefile macros TOPDIR,
 1735     TZDIR, MANDIR, and LIBDIR.  New Makefile macros TZDEFAULT, USRDIR,
 1736     USRSHAREDIR, BINDIR, ZDUMPDIR, and ZICDIR let installers tailor
 1737     locations more precisely.  (This responds to suggestions from
 1738     Brian Inglis and from Steve Summit.)
 1739 
 1740     The default installation procedure no longer creates the
 1741     backward-compatibility link US/Pacific-New, which causes
 1742     confusion during user setup (e.g., see Debian bug 815200).
 1743     Use 'make BACKWARD="backward pacificnew"' to create the link
 1744     anyway, for now.  Eventually we plan to remove the link entirely.
 1745 
 1746     tzdata.zi now contains a version-number comment.
 1747     (Suggested by Tom Lane.)
 1748 
 1749     The Makefile now quotes values like BACKWARD more carefully when
 1750     passing them to the shell.  (Problem reported by Zefram.)
 1751 
 1752     Builders no longer need to specify -DHAVE_SNPRINTF on platforms
 1753     that have snprintf and use pre-C99 compilers.  (Problem reported
 1754     by Jon Skeet.)
 1755 
 1756   Changes to code
 1757 
 1758     zic has a new option -t FILE that specifies the location of the
 1759     file that determines local time when TZ is unset.  The default for
 1760     this location can be configured via the new TZDEFAULT makefile
 1761     macro, which defaults to /etc/localtime.
 1762 
 1763     Diagnostics and commentary now distinguish UT from UTC more
 1764     carefully; see theory.html for more information about UT vs UTC.
 1765 
 1766     zic has been ported to GCC 8's -Wstringop-truncation option.
 1767     (Problem reported by Martin Sebor.)
 1768 
 1769   Changes to documentation and commentary
 1770 
 1771     The zic man page now documents the longstanding behavior that
 1772     times and years can be out of the usual range, with negative times
 1773     counting backwards from midnight and with year 0 preceding year 1.
 1774     (Problem reported by Michael Deckers.)
 1775 
 1776     The theory.html file now mentions the POSIX limit of six chars
 1777     per abbreviation, and lists alphabetic abbreviations used.
 1778 
 1779     The files tz-art.htm and tz-link.htm have been renamed to
 1780     tz-art.html and tz-link.html, respectively, for consistency with
 1781     other file names and to simplify web server configuration.
 1782 
 1783 
 1784 Release 2017c - 2017-10-20 14:49:34 -0700
 1785 
 1786   Briefly:
 1787   Northern Cyprus switches from +03 to +02/+03 on 2017-10-29.
 1788   Fiji ends DST 2018-01-14, not 2018-01-21.
 1789   Namibia switches from +01/+02 to +02 on 2018-04-01.
 1790   Sudan switches from +03 to +02 on 2017-11-01.
 1791   Tonga likely switches from +13/+14 to +13 on 2017-11-05.
 1792   Turks & Caicos switches from -04 to -05/-04 on 2018-11-04.
 1793   A new file tzdata.zi now holds a small text copy of all data.
 1794   The zic input format has been regularized slightly.
 1795 
 1796   Changes to future timestamps
 1797 
 1798     Northern Cyprus has decided to resume EU rules starting
 1799     2017-10-29, thus reinstituting winter time.
 1800 
 1801     Fiji ends DST 2018-01-14 instead of the 2018-01-21 previously
 1802     predicted.  (Thanks to Dominic Fok.)  Adjust future predictions
 1803     accordingly.
 1804 
 1805     Namibia will switch from +01 with DST to +02 all year on
 1806     2017-09-03 at 02:00.  This affects UT offsets starting 2018-04-01
 1807     at 02:00.  (Thanks to Steffen Thorsen.)
 1808 
 1809     Sudan will switch from +03 to +02 on 2017-11-01.  (Thanks to Ahmed
 1810     Atyya and Yahia Abdalla.)  South Sudan is not switching, so
 1811     Africa/Juba is no longer a link to Africa/Khartoum.
 1812 
 1813     Tonga has likely ended its experiment with DST, and will not
 1814     adjust its clocks on 2017-11-05.  Although Tonga has not announced
 1815     whether it will continue to observe DST, the IATA is assuming that
 1816     it will not.  (Thanks to David Wade.)
 1817 
 1818     Turks & Caicos will switch from -04 all year to -05 with US DST on
 1819     2018-03-11 at 03:00.  This affects UT offsets starting 2018-11-04
 1820     at 02:00.  (Thanks to Steffen Thorsen.)
 1821 
 1822   Changes to past timestamps
 1823 
 1824     Namibia switched from +02 to +01 on 1994-03-21, not 1994-04-03.
 1825     (Thanks to Arthur David Olson.)
 1826 
 1827     Detroit did not observe DST in 1967.
 1828 
 1829     Use railway time for Asia/Kolkata before 1941, by switching to
 1830     Madras local time (UT +052110) in 1870, then to IST (UT +0530) in
 1831     1906.  Also, treat 1941-2's +0630 as DST, like 1942-5.
 1832 
 1833     Europe/Dublin's 1946 and 1947 fallback transitions occurred at
 1834     02:00 standard time, not 02:00 DST.  (Thanks to Michael Deckers.)
 1835 
 1836     Pacific/Apia and Pacific/Pago_Pago switched from Antipodean to
 1837     American time in 1892, not 1879.  (Thanks to Michael Deckers.)
 1838 
 1839     Adjust the 1867 transition in Alaska to better reflect the
 1840     historical record, by changing it to occur on 1867-10-18 at 15:30
 1841     Sitka time rather than at the start of 1867-10-17 local time.
 1842     Although strictly speaking this is accurate only for Sitka,
 1843     the rest of Alaska's blanks need to be filled in somehow.
 1844 
 1845     Fix off-by-one errors in UT offsets for Adak and Nome before 1867.
 1846     (Thanks to Michael Deckers.)
 1847 
 1848     Add 7 s to the UT offset in Asia/Yangon before 1920.
 1849 
 1850   Changes to zone names
 1851 
 1852     Remove Canada/East-Saskatchewan from the 'backward' file, as it
 1853     exceeded the 14-character limit and was an unused misnomer anyway.
 1854 
 1855   Changes to build procedure
 1856 
 1857     To support applications that prefer to read time zone data in text
 1858     form, two zic input files tzdata.zi and leapseconds are now
 1859     installed by default.  The commands 'zic tzdata.zi' and 'zic -L
 1860     leapseconds tzdata.zi' can reproduce the tzdata binary files
 1861     without and with leap seconds, respectively.  To prevent these two
 1862     new files from being installed, use 'make TZDATA_TEXT=', and to
 1863     suppress leap seconds from the tzdata text installation, use 'make
 1864     TZDATA_TEXT=tzdata.zi'.
 1865 
 1866     'make BACKWARD=' now suppresses backward-compatibility names
 1867     like 'US/Pacific' that are defined in the 'backward' and
 1868     'pacificnew' files.
 1869 
 1870     'make check' now works on systems that lack a UTF-8 locale,
 1871     or that lack the nsgmls program.  Set UTF8_LOCALE to configure
 1872     the name of a UTF-8 locale, if you have one.
 1873 
 1874     Y2K runtime checks are no longer enabled by default.  Add
 1875     -DDEPRECATE_TWO_DIGIT_YEARS to CFLAGS to enable them, instead of
 1876     adding -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
 1877     to disable them.  (New name suggested by Brian Inglis.)
 1878 
 1879     The build procedure for zdump now works on AIX 7.1.
 1880     (Problem reported by Kees Dekker.)
 1881 
 1882   Changes to code
 1883 
 1884     zic and the reference runtime now reject multiple leap seconds
 1885     within 28 days of each other, or leap seconds before the Epoch.
 1886     As a result, support for double leap seconds, which was
 1887     obsolescent and undocumented, has been removed.  Double leap
 1888     seconds were an error in the C89 standard; they have never existed
 1889     in civil timekeeping.  (Thanks to Robert Elz and Bradley White for
 1890     noticing glitches in the code that uncovered this problem.)
 1891 
 1892     zic now warns about use of the obsolescent and undocumented -y
 1893     option, and about use of the obsolescent TYPE field of Rule lines.
 1894 
 1895     zic now allows unambiguous abbreviations like "Sa" and "Su" for
 1896     weekdays; formerly it rejected them due to a bug.  Conversely, zic
 1897     no longer considers non-prefixes to be abbreviations; for example,
 1898     it no longer accepts "lF" as an abbreviation for "lastFriday".
 1899     Also, zic warns about the undocumented usage with a "last-"
 1900     prefix, e.g., "last-Fri".
 1901 
 1902     Similarly, zic now accepts the unambiguous abbreviation "L" for
 1903     "Link" in ordinary context and for "Leap" in leap-second context.
 1904     Conversely, zic no longer accepts non-prefixes such as "La" as
 1905     abbreviations for words like "Leap".
 1906 
 1907     zic no longer accepts leap second lines in ordinary input, or
 1908     ordinary lines in leap second input.  Formerly, zic sometimes
 1909     warned about this undocumented usage and handled it incorrectly.
 1910 
 1911     The new macro HAVE_TZNAME governs whether the tzname external
 1912     variable is exported, instead of USG_COMPAT.  USG_COMPAT now
 1913     governs only the external variables "timezone" and "daylight".
 1914     This change is needed because the three variables are not in the
 1915     same category: although POSIX requires tzname, it specifies the
 1916     other two variables as optional.  Also, USG_COMPAT is now 1 or 0:
 1917     if not defined, the code attempts to guess it from other macros.
 1918 
 1919     localtime.c and difftime.c no longer require stdio.h, and .c files
 1920     other than zic.c no longer require sys/wait.h.
 1921 
 1922     zdump.c no longer assumes snprintf.  (Reported by Jonathan Leffler.)
 1923 
 1924     Calculation of time_t extrema works around a bug in GCC 4.8.4
 1925     (Reported by Stan Shebs and Joseph Myers.)
 1926 
 1927     zic.c no longer mistranslates formats of line numbers in non-English
 1928     locales.  (Problem reported by Benno Schulenberg.)
 1929 
 1930     Several minor changes have been made to the code to make it a
 1931     bit easier to port to MS-Windows and Solaris.  (Thanks to Kees
 1932     Dekker for reporting the problems.)
 1933 
 1934   Changes to documentation and commentary
 1935 
 1936     The two new files 'theory.html' and 'calendars' contain the
 1937     contents of the removed file 'Theory'.  The goal is to document
 1938     tzdb theory more accessibly.
 1939 
 1940     The zic man page now documents abbreviation rules.
 1941 
 1942     tz-link.htm now covers how to apply tzdata changes to clients.
 1943     (Thanks to Jorge Fábregas for the AIX link.)  It also mentions MySQL.
 1944 
 1945     The leap-seconds.list URL has been updated to something that is
 1946     more reliable for tzdb.  (Thanks to Tim Parenti and Brian Inglis.)
 1947 
 1948 Release 2017b - 2017-03-17 07:30:38 -0700
 1949 
 1950   Briefly: Haiti has resumed DST.
 1951 
 1952   Changes to past and future timestamps
 1953 
 1954     Haiti resumed observance of DST in 2017.  (Thanks to Steffen Thorsen.)
 1955 
 1956   Changes to past timestamps
 1957 
 1958     Liberia changed from -004430 to +00 on 1972-01-07, not 1972-05-01.
 1959 
 1960     Use "MMT" to abbreviate Liberia's time zone before 1972, as "-004430"
 1961     is one byte over the POSIX limit.  (Problem reported by Derick Rethans.)
 1962 
 1963   Changes to code
 1964 
 1965     The reference localtime implementation now falls back on the
 1966     current US daylight-saving transition rules rather than the
 1967     1987-2006 rules.  This fallback occurs only when (1) the TZ
 1968     environment variable has a value like "AST4ADT" that asks
 1969     for daylight saving time but does not specify the rules, (2) there
 1970     is no file by that name, and (3) the TZDEFRULES file cannot be
 1971     loaded.  (Thanks to Tom Lane.)
 1972 
 1973 
 1974 Release 2017a - 2017-02-28 00:05:36 -0800
 1975 
 1976   Briefly: Southern Chile moves from -04/-03 to -03, and Mongolia
 1977   discontinues DST.
 1978 
 1979   Changes to future timestamps
 1980 
 1981     Mongolia no longer observes DST.  (Thanks to Ganbold Tsagaankhuu.)
 1982 
 1983     Chile's Region of Magallanes moves from -04/-03 to -03 year-round.
 1984     Its clocks diverge from America/Santiago starting 2017-05-13 at
 1985     23:00, hiving off a new zone America/Punta_Arenas.  Although the
 1986     Chilean government says this change expires in May 2019, for now
 1987     assume it's permanent.  (Thanks to Juan Correa and Deborah
 1988     Goldsmith.)  This also affects Antarctica/Palmer.
 1989 
 1990   Changes to past timestamps
 1991 
 1992     Fix many entries for historical timestamps for Europe/Madrid
 1993     before 1979, to agree with tables compiled by Pere Planesas of the
 1994     National Astronomical Observatory of Spain.  As a side effect,
 1995     this changes some timestamps for Africa/Ceuta before 1929, which
 1996     are probably guesswork anyway.  (Thanks to Steve Allen and
 1997     Pierpaolo Bernardi for the heads-ups, and to Michael Deckers for
 1998     correcting the 1901 transition.)
 1999 
 2000     Ecuador observed DST from 1992-11-28 to 1993-02-05.
 2001     (Thanks to Alois Treindl.)
 2002 
 2003     Asia/Atyrau and Asia/Oral were at +03 (not +04) before 1930-06-21.
 2004     (Thanks to Stepan Golosunov.)
 2005 
 2006   Changes to past and future time zone abbreviations
 2007 
 2008     Switch to numeric time zone abbreviations for South America, as
 2009     part of the ongoing project of removing invented abbreviations.
 2010     This avoids the need to invent an abbreviation for the new Chilean
 2011     new zone.  Similarly, switch from invented to numeric time zone
 2012     abbreviations for Afghanistan, American Samoa, the Azores,
 2013     Bangladesh, Bhutan, the British Indian Ocean Territory, Brunei,
 2014     Cape Verde, Chatham Is, Christmas I, Cocos (Keeling) Is, Cook Is,
 2015     Dubai, East Timor, Eucla, Fiji, French Polynesia, Greenland,
 2016     Indochina, Iran, Iraq, Kiribati, Lord Howe, Macquarie, Malaysia,
 2017     the Maldives, Marshall Is, Mauritius, Micronesia, Mongolia,
 2018     Myanmar, Nauru, Nepal, New Caledonia, Niue, Norfolk I, Palau,
 2019     Papua New Guinea, the Philippines, Pitcairn, Qatar, Réunion, St
 2020     Pierre & Miquelon, Samoa, Saudi Arabia, Seychelles, Singapore,
 2021     Solomon Is, Tokelau, Tuvalu, Wake, Vanuatu, Wallis & Futuna, and
 2022     Xinjiang; for 20-minute daylight saving time in Ghana before 1943;
 2023     for half-hour daylight saving time in Belize before 1944 and in
 2024     the Dominican Republic before 1975; and for Canary Islands before
 2025     1946, for Guinea-Bissau before 1975, for Iceland before 1969, for
 2026     Indian Summer Time before 1942, for Indonesia before around 1964,
 2027     for Kenya before 1960, for Liberia before 1973, for Madeira before
 2028     1967, for Namibia before 1943, for the Netherlands in 1937-9, for
 2029     Pakistan before 1971, for Western Sahara before 1977, and for
 2030     Zaporozhye in 1880-1924.
 2031 
 2032     For Alaska time from 1900 through 1967, instead of "CAT" use the
 2033     abbreviation "AST", the abbreviation commonly used at the time
 2034     (Atlantic Standard Time had not been standardized yet).  Use "AWT"
 2035     and "APT" instead of the invented abbreviations "CAWT" and "CAPT".
 2036 
 2037     Use "CST" and "CDT" instead of invented abbreviations for Macau
 2038     before 1999 and Taiwan before 1938, and use "JST" instead of the
 2039     invented abbreviation "JCST" for Japan and Korea before 1938.
 2040 
 2041   Change to database entry category
 2042 
 2043     Move the Pacific/Johnston link from 'australasia' to 'backward',
 2044     since Johnston is now uninhabited.
 2045 
 2046   Changes to code
 2047 
 2048     zic no longer mishandles some transitions in January 2038 when it
 2049     attempts to work around Qt bug 53071.  This fixes a bug affecting
 2050     Pacific/Tongatapu that was introduced in zic 2016e.  localtime.c
 2051     now contains a workaround, useful when loading a file generated by
 2052     a buggy zic.  (Problem and localtime.c fix reported by Bradley
 2053     White.)
 2054 
 2055     zdump -i now outputs non-hour numeric time zone abbreviations
 2056     without a colon, e.g., "+0530" rather than "+05:30".  This agrees
 2057     with zic %z and with common practice, and simplifies auditing of
 2058     zdump output.
 2059 
 2060     zdump is now buildable again with -DUSE_LTZ=0.
 2061     (Problem reported by Joseph Myers.)
 2062 
 2063     zdump.c now always includes private.h, to avoid code duplication
 2064     with private.h.  (Problem reported by Kees Dekker.)
 2065 
 2066     localtime.c no longer mishandles early or late timestamps
 2067     when TZ is set to a POSIX-style string that specifies DST.
 2068     (Problem reported by Kees Dekker.)
 2069 
 2070     date and strftime now cause %z to generate "-0000" instead of
 2071     "+0000" when the UT offset is zero and the time zone abbreviation
 2072     begins with "-".
 2073 
 2074   Changes to documentation and commentary
 2075 
 2076     The 'Theory' file now better documents choice of historical time
 2077     zone abbreviations.  (Problems reported by Michael Deckers.)
 2078 
 2079     tz-link.htm now covers leap smearing, which is popular in clouds.
 2080 
 2081 
 2082 Release 2016j - 2016-11-22 23:17:13 -0800
 2083 
 2084   Briefly: Saratov, Russia moves from +03 to +04 on 2016-12-04.
 2085 
 2086   Changes to future timestamps
 2087 
 2088     Saratov, Russia switches from +03 to +04 on 2016-12-04 at 02:00.
 2089     This hives off a new zone Europe/Saratov from Europe/Volgograd.
 2090     (Thanks to Yuri Konotopov and Stepan Golosunov.)
 2091 
 2092   Changes to past timestamps
 2093 
 2094     The new zone Asia/Atyrau for Atyraū Region, Kazakhstan, is like
 2095     Asia/Aqtau except it switched from +05/+06 to +04/+05 in spring
 2096     1999, not fall 1994.  (Thanks to Stepan Golosunov.)
 2097 
 2098   Changes to past time zone abbreviations
 2099 
 2100     Asia/Gaza and Asia/Hebron now use "EEST", not "EET", to denote
 2101     summer time before 1948.  The old use of "EET" was a typo.
 2102 
 2103   Changes to code
 2104 
 2105     zic no longer mishandles file systems that lack hard links, fixing
 2106     bugs introduced in 2016g.  (Problems reported by Tom Lane.)
 2107     Also, when the destination already contains symbolic links, zic
 2108     should now work better on systems where the 'link' system call
 2109     does not follow symbolic links.
 2110 
 2111   Changes to documentation and commentary
 2112 
 2113     tz-link.htm now documents the relationship between release version
 2114     numbers and development-repository commit tags.  (Suggested by
 2115     Paul Koning.)
 2116 
 2117     The 'Theory' file now documents UT.
 2118 
 2119     iso3166.tab now accents "Curaçao", and commentary now mentions
 2120     the names "Cabo Verde" and "Czechia".  (Thanks to Jiří Boháč.)
 2121 
 2122 
 2123 Release 2016i - 2016-11-01 23:19:52 -0700
 2124 
 2125   Briefly: Cyprus split into two time zones on 2016-10-30, and Tonga
 2126   reintroduces DST on 2016-11-06.
 2127 
 2128   Changes to future timestamps
 2129 
 2130     Pacific/Tongatapu begins DST on 2016-11-06 at 02:00, ending on
 2131     2017-01-15 at 03:00.  Assume future observances in Tonga will be
 2132     from the first Sunday in November through the third Sunday in
 2133     January, like Fiji.  (Thanks to Pulu ʻAnau.)  Switch to numeric
 2134     time zone abbreviations for this zone.
 2135 
 2136   Changes to past and future timestamps
 2137 
 2138     Northern Cyprus is now +03 year round, causing a split in Cyprus
 2139     time zones starting 2016-10-30 at 04:00.  This creates a zone
 2140     Asia/Famagusta.  (Thanks to Even Scharning and Matt Johnson.)
 2141 
 2142     Antarctica/Casey switched from +08 to +11 on 2016-10-22.
 2143     (Thanks to Steffen Thorsen.)
 2144 
 2145   Changes to past timestamps
 2146 
 2147     Several corrections were made for pre-1975 timestamps in Italy.
 2148     These affect Europe/Malta, Europe/Rome, Europe/San_Marino, and
 2149     Europe/Vatican.
 2150 
 2151     First, the 1893-11-01 00:00 transition in Italy used the new UT
 2152     offset (+01), not the old (+00:49:56).  (Thanks to Michael
 2153     Deckers.)
 2154 
 2155     Second, rules for daylight saving in Italy were changed to agree
 2156     with Italy's National Institute of Metrological Research (INRiM)
 2157     except for 1944, as follows (thanks to Pierpaolo Bernardi, Brian
 2158     Inglis, and Michael Deckers):
 2159 
 2160       The 1916-06-03 transition was at 24:00, not 00:00.
 2161 
 2162       The 1916-10-01, 1919-10-05, and 1920-09-19 transitions were at
 2163       00:00, not 01:00.
 2164 
 2165       The 1917-09-30 and 1918-10-06 transitions were at 24:00, not
 2166       01:00.
 2167 
 2168       The 1944-09-17 transition was at 03:00, not 01:00.  This
 2169       particular change is taken from Italian law as INRiM's table,
 2170       (which says 02:00) appears to have a typo here.  Also, keep the
 2171       1944-04-03 transition for Europe/Rome, as Rome was controlled by
 2172       Germany then.
 2173 
 2174       The 1967-1970 and 1972-1974 fallback transitions were at 01:00,
 2175       not 00:00.
 2176 
 2177   Changes to code
 2178 
 2179     The code should now be buildable on AmigaOS merely by setting the
 2180     appropriate Makefile variables.  (From a patch by Carsten Larsen.)
 2181 
 2182 
 2183 Release 2016h - 2016-10-19 23:17:57 -0700
 2184 
 2185   Changes to future timestamps
 2186 
 2187     Asia/Gaza and Asia/Hebron end DST on 2016-10-29 at 01:00, not
 2188     2016-10-21 at 00:00.  (Thanks to Sharef Mustafa.)  Predict that
 2189     future fall transitions will be on the last Saturday of October
 2190     at 01:00, which is consistent with predicted spring transitions
 2191     on the last Saturday of March.  (Thanks to Tim Parenti.)
 2192 
 2193   Changes to past timestamps
 2194 
 2195     In Turkey, transitions in 1986-1990 were at 01:00 standard time
 2196     not at 02:00, and the spring 1994 transition was on March 20, not
 2197     March 27.  (Thanks to Kıvanç Yazan.)
 2198 
 2199   Changes to past and future time zone abbreviations
 2200 
 2201     Asia/Colombo now uses numeric time zone abbreviations like "+0530"
 2202     instead of alphabetic ones like "IST" and "LKT".  Various
 2203     English-language sources use "IST", "LKT" and "SLST", with no
 2204     working consensus.  (Usage of "SLST" mentioned by Sadika
 2205     Sumanapala.)
 2206 
 2207   Changes to code
 2208 
 2209     zic no longer mishandles relativizing file names when creating
 2210     symbolic links like /etc/localtime, when these symbolic links
 2211     are outside the usual directory hierarchy.  This fixes a bug
 2212     introduced in 2016g.  (Problem reported by Andreas Stieger.)
 2213 
 2214   Changes to build procedure
 2215 
 2216     New rules 'traditional_tarballs' and 'traditional_signatures' for
 2217     building just the traditional-format distribution.  (Requested by
 2218     Deborah Goldsmith.)
 2219 
 2220     The file 'version' is now put into the tzdata tarball too.
 2221     (Requested by Howard Hinnant.)
 2222 
 2223   Changes to documentation and commentary
 2224 
 2225     The 'Theory' file now has a section on interface stability.
 2226     (Requested by Paul Koning.)  It also mentions features like
 2227     tm_zone and localtime_rz that have long been supported by the
 2228     reference code.
 2229 
 2230     tz-link.htm has improved coverage of time zone boundaries suitable
 2231     for geolocation.  (Thanks to heads-ups from Evan Siroky and Matt
 2232     Johnson.)
 2233 
 2234     The US commentary now mentions Allen and the "day of two noons".
 2235 
 2236     The Fiji commentary mentions the government's 2016-10-03 press
 2237     release.  (Thanks to Raymond Kumar.)
 2238 
 2239 
 2240 Release 2016g - 2016-09-13 08:56:38 -0700
 2241 
 2242   Changes to future timestamps
 2243 
 2244     Turkey switched from EET/EEST (+02/+03) to permanent +03,
 2245     effective 2016-09-07.  (Thanks to Burak AYDIN.)  Use "+03" rather
 2246     than an invented abbreviation for the new time.
 2247 
 2248     New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52.
 2249     (Thanks to Tim Parenti.)
 2250 
 2251   Changes to past timestamps
 2252 
 2253     For America/Los_Angeles, spring-forward transition times have been
 2254     corrected from 02:00 to 02:01 in 1948, and from 02:00 to 01:00 in
 2255     1950-1966.
 2256 
 2257     For zones using Soviet time on 1919-07-01, transitions to UT-based
 2258     time were at 00:00 UT, not at 02:00 local time.  The affected
 2259     zones are Europe/Kirov, Europe/Moscow, Europe/Samara, and
 2260     Europe/Ulyanovsk.  (Thanks to Alexander Belopolsky.)
 2261 
 2262   Changes to past and future time zone abbreviations
 2263 
 2264     The Factory zone now uses the time zone abbreviation -00 instead
 2265     of a long English-language string, as -00 is now the normal way to
 2266     represent an undefined time zone.
 2267 
 2268     Several zones in Antarctica and the former Soviet Union, along
 2269     with zones intended for ships at sea that cannot use POSIX TZ
 2270     strings, now use numeric time zone abbreviations instead of
 2271     invented or obsolete alphanumeric abbreviations.  The affected
 2272     zones are Antarctica/Casey, Antarctica/Davis,
 2273     Antarctica/DumontDUrville, Antarctica/Mawson, Antarctica/Rothera,
 2274     Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok,
 2275     Asia/Anadyr, Asia/Ashgabat, Asia/Baku, Asia/Bishkek, Asia/Chita,
 2276     Asia/Dushanbe, Asia/Irkutsk, Asia/Kamchatka, Asia/Khandyga,
 2277     Asia/Krasnoyarsk, Asia/Magadan, Asia/Omsk, Asia/Sakhalin,
 2278     Asia/Samarkand, Asia/Srednekolymsk, Asia/Tashkent, Asia/Tbilisi,
 2279     Asia/Ust-Nera, Asia/Vladivostok, Asia/Yakutsk, Asia/Yekaterinburg,
 2280     Asia/Yerevan, Etc/GMT-14, Etc/GMT-13, Etc/GMT-12, Etc/GMT-11,
 2281     Etc/GMT-10, Etc/GMT-9, Etc/GMT-8, Etc/GMT-7, Etc/GMT-6, Etc/GMT-5,
 2282     Etc/GMT-4, Etc/GMT-3, Etc/GMT-2, Etc/GMT-1, Etc/GMT+1, Etc/GMT+2,
 2283     Etc/GMT+3, Etc/GMT+4, Etc/GMT+5, Etc/GMT+6, Etc/GMT+7, Etc/GMT+8,
 2284     Etc/GMT+9, Etc/GMT+10, Etc/GMT+11, Etc/GMT+12, Europe/Kaliningrad,
 2285     Europe/Minsk, Europe/Samara, Europe/Volgograd, and
 2286     Indian/Kerguelen.  For Europe/Moscow the invented abbreviation MSM
 2287     was replaced by +05, whereas MSK and MSD were kept as they are not
 2288     our invention and are widely used.
 2289 
 2290   Changes to zone names
 2291 
 2292     Rename Asia/Rangoon to Asia/Yangon, with a backward compatibility link.
 2293     (Thanks to David Massoud.)
 2294 
 2295   Changes to code
 2296 
 2297     zic no longer generates binary files containing POSIX TZ-like
 2298     strings that disagree with the local time type after the last
 2299     explicit transition in the data.  This fixes a bug with
 2300     Africa/Casablanca and Africa/El_Aaiun in some year-2037 timestamps
 2301     on the reference platform.  (Thanks to Alexander Belopolsky for
 2302     reporting the bug and suggesting a way forward.)
 2303 
 2304     If the installed localtime and/or posixrules files are symbolic
 2305     links, zic now keeps them symbolic links when updating them, for
 2306     compatibility with platforms like OpenSUSE where other programs
 2307     configure these files as symlinks.
 2308 
 2309     zic now avoids hard linking to symbolic links, avoids some
 2310     unnecessary mkdir and stat system calls, and uses shorter file
 2311     names internally.
 2312 
 2313     zdump has a new -i option to generate transitions in a
 2314     more-compact but still human-readable format.  This option is
 2315     experimental, and the output format may change in future versions.
 2316     (Thanks to Jon Skeet for suggesting that an option was needed,
 2317     and thanks to Tim Parenti and Chris Rovick for further comments.)
 2318 
 2319   Changes to build procedure
 2320 
 2321     An experimental distribution format is available, in addition
 2322     to the traditional format which will continue to be distributed.
 2323     The new format is a tarball tzdb-VERSION.tar.lz with signature
 2324     file tzdb-VERSION.tar.lz.asc.  It unpacks to a top-level directory
 2325     tzdb-VERSION containing the code and data of the traditional
 2326     two-tarball format, along with extra data that may be useful.
 2327     (Thanks to Antonio Diaz Diaz, Oscar van Vlijmen, and many others
 2328     for comments about the experimental format.)
 2329 
 2330     The release version number is now more accurate in the usual case
 2331     where releases are built from a Git repository.  For example, if
 2332     23 commits and some working-file changes have been made since
 2333     release 2016g, the version number is now something like
 2334     '2016g-23-g50556e3-dirty' instead of the misleading '2016g'.
 2335     Tagged releases use the same version number format as before,
 2336     e.g., '2016g'.  To support the more-accurate version number, its
 2337     specification has moved from a line in the Makefile to a new
 2338     source file 'version'.
 2339 
 2340     The experimental distribution contains a file to2050.tzs that
 2341     contains what should be the output of 'zdump -i -c 2050' on
 2342     primary zones.  If this file is available, 'make check' now checks
 2343     that zdump generates this output.
 2344 
 2345     'make check_web' now works on Fedora-like distributions.
 2346 
 2347   Changes to documentation and commentary
 2348 
 2349     tzfile.5 now documents the new restriction on POSIX TZ-like
 2350     strings that is now implemented by zic.
 2351 
 2352     Comments now cite URLs for some 1917-1921 Russian DST decrees.
 2353     (Thanks to Alexander Belopolsky.)
 2354 
 2355     tz-link.htm mentions JuliaTime (thanks to Curtis Vogt) and Time4J
 2356     (thanks to Meno Hochschild) and ThreeTen-Extra, and its
 2357     description of Java 8 has been brought up to date (thanks to
 2358     Stephen Colebourne).  Its description of local time on Mars has
 2359     been updated to match current practice, and URLs have been updated
 2360     and some obsolete ones removed.
 2361 
 2362 
 2363 Release 2016f - 2016-07-05 16:26:51 +0200
 2364 
 2365   Changes affecting future timestamps
 2366 
 2367     The Egyptian government changed its mind on short notice, and
 2368     Africa/Cairo will not introduce DST starting 2016-07-07 after all.
 2369     (Thanks to Mina Samuel.)
 2370 
 2371     Asia/Novosibirsk switches from +06 to +07 on 2016-07-24 at 02:00.
 2372     (Thanks to Stepan Golosunov.)
 2373 
 2374   Changes to past and future timestamps
 2375 
 2376     Asia/Novokuznetsk and Asia/Novosibirsk now use numeric time zone
 2377     abbreviations instead of invented ones.
 2378 
 2379   Changes affecting past timestamps
 2380 
 2381     Europe/Minsk's 1992-03-29 spring-forward transition was at 02:00 not 00:00.
 2382     (Thanks to Stepan Golosunov.)
 2383 
 2384 
 2385 Release 2016e - 2016-06-14 08:46:16 -0700
 2386 
 2387   Changes affecting future timestamps
 2388 
 2389     Africa/Cairo observes DST in 2016 from July 7 to the end of October.
 2390     Guess October 27 and 24:00 transitions.  (Thanks to Steffen Thorsen.)
 2391     For future years, guess April's last Thursday to October's last
 2392     Thursday except for Ramadan.
 2393 
 2394   Changes affecting past timestamps
 2395 
 2396     Locations while uninhabited now use '-00', not 'zzz', as a
 2397     placeholder time zone abbreviation.  This is inspired by Internet
 2398     RFC 3339 and is more consistent with numeric time zone
 2399     abbreviations already used elsewhere.  The change affects several
 2400     arctic and antarctic locations, e.g., America/Cambridge_Bay before
 2401     1920 and Antarctica/Troll before 2005.
 2402 
 2403     Asia/Baku's 1992-09-27 transition from +04 (DST) to +04 (non-DST) was
 2404     at 03:00, not 23:00 the previous day.  (Thanks to Michael Deckers.)
 2405 
 2406   Changes to code
 2407 
 2408     zic now outputs a dummy transition at time 2**31 - 1 in zones
 2409     whose POSIX-style TZ strings contain a '<'.  This mostly works
 2410     around Qt bug 53071 <https://bugreports.qt.io/browse/QTBUG-53071>.
 2411     (Thanks to Zhanibek Adilbekov for reporting the Qt bug.)
 2412 
 2413   Changes affecting documentation and commentary
 2414 
 2415     tz-link.htm says why governments should give plenty of notice for
 2416     time zone or DST changes, and refers to Matt Johnson's blog post.
 2417 
 2418     tz-link.htm mentions Tzdata for Elixir.  (Thanks to Matt Johnson.)
 2419 
 2420 
 2421 Release 2016d - 2016-04-17 22:50:29 -0700
 2422 
 2423   Changes affecting future timestamps
 2424 
 2425     America/Caracas switches from -0430 to -04 on 2016-05-01 at 02:30.
 2426     (Thanks to Alexander Krivenyshev for the heads-up.)
 2427 
 2428     Asia/Magadan switches from +10 to +11 on 2016-04-24 at 02:00.
 2429     (Thanks to Alexander Krivenyshev and Matt Johnson.)
 2430 
 2431     New zone Asia/Tomsk, split off from Asia/Novosibirsk.  It covers
 2432     Tomsk Oblast, Russia, which switches from +06 to +07 on 2016-05-29
 2433     at 02:00.  (Thanks to Stepan Golosunov.)
 2434 
 2435   Changes affecting past timestamps
 2436 
 2437     New zone Europe/Kirov, split off from Europe/Volgograd.  It covers
 2438     Kirov Oblast, Russia, which switched from +04/+05 to +03/+04 on
 2439     1989-03-26 at 02:00, roughly a year after Europe/Volgograd made
 2440     the same change.  (Thanks to Stepan Golosunov.)
 2441 
 2442     Russia and nearby locations had daylight-saving transitions on
 2443     1992-03-29 at 02:00 and 1992-09-27 at 03:00, instead of on
 2444     1992-03-28 at 23:00 and 1992-09-26 at 23:00.  (Thanks to Stepan
 2445     Golosunov.)
 2446 
 2447     Many corrections to historical time in Kazakhstan from 1991
 2448     through 2005.  (Thanks to Stepan Golosunov.)  Replace Kazakhstan's
 2449     invented time zone abbreviations with numeric abbreviations.
 2450 
 2451   Changes to commentary
 2452 
 2453     Mention Internet RFCs 7808 (TZDIST) and 7809 (CalDAV time zone references).
 2454 
 2455 
 2456 Release 2016c - 2016-03-23 00:51:27 -0700
 2457 
 2458   Changes affecting future timestamps
 2459 
 2460     Azerbaijan no longer observes DST.  (Thanks to Steffen Thorsen.)
 2461 
 2462     Chile reverts from permanent to seasonal DST.  (Thanks to Juan
 2463     Correa for the heads-up, and to Tim Parenti for corrections.)
 2464     Guess that future transitions are August's and May's second
 2465     Saturdays at 24:00 mainland time.  Also, call the period from
 2466     2014-09-07 through 2016-05-14 daylight saving time instead of
 2467     standard time, as that seems more appropriate now.
 2468 
 2469   Changes affecting past timestamps
 2470 
 2471     Europe/Kaliningrad and Europe/Vilnius changed from +03/+04 to
 2472     +02/+03 on 1989-03-26, not 1991-03-31.  Europe/Volgograd changed
 2473     from +04/+05 to +03/+04 on 1988-03-27, not 1989-03-26.
 2474     (Thanks to Stepan Golosunov.)
 2475 
 2476   Changes to commentary
 2477 
 2478     Several updates and URLs for historical and proposed Russian changes.
 2479     (Thanks to Stepan Golosunov, Matt Johnson, and Alexander Krivenyshev.)
 2480 
 2481 
 2482 Release 2016b - 2016-03-12 17:30:14 -0800
 2483 
 2484   Compatibility note
 2485 
 2486     Starting with release 2016b, some data entries cause zic implementations
 2487     derived from tz releases 2005j through 2015e to issue warnings like
 2488     "time zone abbreviation differs from POSIX standard (+03)".
 2489     These warnings should not otherwise affect zic's output and can safely be
 2490     ignored on today's platforms, as the warnings refer to a restriction in
 2491     POSIX.1-1988 that was removed in POSIX.1-2001.  One way to suppress the
 2492     warnings is to upgrade to zic derived from tz releases 2015f and later.
 2493 
 2494   Changes affecting future timestamps
 2495 
 2496     New zones Europe/Astrakhan and Europe/Ulyanovsk for Astrakhan and
 2497     Ulyanovsk Oblasts, Russia, both of which will switch from +03 to +04 on
 2498     2016-03-27 at 02:00 local time.  They need distinct zones since their
 2499     post-1970 histories disagree.  New zone Asia/Barnaul for Altai Krai and
 2500     Altai Republic, Russia, which will switch from +06 to +07 on the same date
 2501     and local time.  The Astrakhan change is already official; the others have
 2502     passed the first reading in the State Duma and are extremely likely.
 2503     Also, Asia/Sakhalin moves from +10 to +11 on 2016-03-27 at 02:00.
 2504     (Thanks to Alexander Krivenyshev for the heads-up, and to Matt Johnson
 2505     and Stepan Golosunov for followup.)
 2506 
 2507     As a trial of a new system that needs less information to be made up,
 2508     the new zones use numeric time zone abbreviations like "+04"
 2509     instead of invented abbreviations like "ASTT".
 2510 
 2511     Haiti will not observe DST in 2016.  (Thanks to Jean Antoine via
 2512     Steffen Thorsen.)
 2513 
 2514     Palestine's spring-forward transition on 2016-03-26 is at 01:00, not 00:00.
 2515     (Thanks to Hannah Kreitem.) Guess future transitions will be March's last
 2516     Saturday at 01:00, not March's last Friday at 24:00.
 2517 
 2518   Changes affecting past timestamps
 2519 
 2520     Europe/Chisinau observed DST during 1990, and switched from +04 to
 2521     +03 at 1990-05-06 02:00, instead of switching from +03 to +02.
 2522     (Thanks to Stepan Golosunov.)
 2523 
 2524     1991 abbreviations in Europe/Samara should be SAMT/SAMST, not
 2525     KUYT/KUYST.  (Thanks to Stepan Golosunov.)
 2526 
 2527   Changes to code
 2528 
 2529     tzselect's diagnostics and checking, and checktab.awk's checking,
 2530     have been improved.  (Thanks to J William Piggott.)
 2531 
 2532     tzcode now builds under MinGW.  (Thanks to Ian Abbott and Esben Haabendal.)
 2533 
 2534     tzselect now tests Julian-date TZ settings more accurately.
 2535     (Thanks to J William Piggott.)
 2536 
 2537   Changes to commentary
 2538 
 2539     Comments in zone tables have been improved.  (Thanks to J William Piggott.)
 2540 
 2541     tzselect again limits its menu comments so that menus fit on a
 2542     24×80 alphanumeric display.
 2543 
 2544     A new web page tz-how-to.html.  (Thanks to Bill Seymour.)
 2545 
 2546     In the Theory file, the description of possible time zone abbreviations in
 2547     tzdata has been cleaned up, as the old description was unclear and
 2548     inconsistent.  (Thanks to Alain Mouette for reporting the problem.)
 2549 
 2550 
 2551 Release 2016a - 2016-01-26 23:28:02 -0800
 2552 
 2553   Changes affecting future timestamps
 2554 
 2555     America/Cayman will not observe daylight saving this year after all.
 2556     Revert our guess that it would.  (Thanks to Matt Johnson.)
 2557 
 2558     Asia/Chita switches from +0800 to +0900 on 2016-03-27 at 02:00.
 2559     (Thanks to Alexander Krivenyshev.)
 2560 
 2561     Asia/Tehran now has DST predictions for the year 2038 and later,
 2562     to be March 21 00:00 to September 21 00:00.  This is likely better
 2563     than predicting no DST, albeit off by a day every now and then.
 2564 
 2565   Changes affecting past and future timestamps
 2566 
 2567     America/Metlakatla switched from PST all year to AKST/AKDT on
 2568     2015-11-01 at 02:00.  (Thanks to Steffen Thorsen.)
 2569 
 2570     America/Santa_Isabel has been removed, and replaced with a
 2571     backward compatibility link to America/Tijuana.  Its contents were
 2572     apparently based on a misreading of Mexican legislation.
 2573 
 2574   Changes affecting past timestamps
 2575 
 2576     Asia/Karachi's two transition times in 2002 were off by a minute.
 2577     (Thanks to Matt Johnson.)
 2578 
 2579   Changes affecting build procedure
 2580 
 2581     An installer can now combine leap seconds with use of the backzone file,
 2582     e.g., with 'make PACKRATDATA=backzone REDO=posix_right zones'.
 2583     The old 'make posix_packrat' rule is now marked as obsolescent.
 2584     (Thanks to Ian Abbott for an initial implementation.)
 2585 
 2586   Changes affecting documentation and commentary
 2587 
 2588     A new file LICENSE makes it easier to see that the code and data
 2589     are mostly public-domain.  (Thanks to James Knight.)  The three
 2590     non-public-domain files now use the current (3-clause) BSD license
 2591     instead of older versions of that license.
 2592 
 2593     tz-link.htm mentions the BDE library (thanks to Andrew Paprocki),
 2594     CCTZ (thanks to Tim Parenti), TimeJones.com, and has a new section
 2595     on editing tz source files (with a mention of Sublime zoneinfo,
 2596     thanks to Gilmore Davidson).
 2597 
 2598     The Theory and asia files now mention the 2015 book "The Global
 2599     Transformation of Time, 1870-1950", and cite a couple of reviews.
 2600 
 2601     The America/Chicago entry now documents the informal use of US
 2602     central time in Fort Pierre, South Dakota.  (Thanks to Rick
 2603     McDermid, Matt Johnson, and Steve Jones.)
 2604 
 2605 
 2606 Release 2015g - 2015-10-01 00:39:51 -0700
 2607 
 2608   Changes affecting future timestamps
 2609 
 2610     Turkey's 2015 fall-back transition is scheduled for Nov. 8, not Oct. 25.
 2611     (Thanks to Fatih.)
 2612 
 2613     Norfolk moves from +1130 to +1100 on 2015-10-04 at 02:00 local time.
 2614     (Thanks to Alexander Krivenyshev.)
 2615 
 2616     Fiji's 2016 fall-back transition is scheduled for January 17, not 24.
 2617     (Thanks to Ken Rylander.)
 2618 
 2619     Fort Nelson, British Columbia will not fall back on 2015-11-01.  It has
 2620     effectively been on MST (-0700) since it advanced its clocks on 2015-03-08.
 2621     New zone America/Fort_Nelson.  (Thanks to Matt Johnson.)
 2622 
 2623   Changes affecting past timestamps
 2624 
 2625     Norfolk observed DST from 1974-10-27 02:00 to 1975-03-02 02:00.
 2626 
 2627   Changes affecting code
 2628 
 2629     localtime no longer mishandles America/Anchorage after 2037.
 2630     (Thanks to Bradley White for reporting the bug.)
 2631 
 2632     On hosts with signed 32-bit time_t, localtime no longer mishandles
 2633     Pacific/Fiji after 2038-01-16 14:00 UTC.
 2634 
 2635     The localtime module allows the variables 'timezone', 'daylight',
 2636     and 'altzone' to be in common storage shared with other modules,
 2637     and declares them in case the system <time.h> does not.
 2638     (Problems reported by Kees Dekker.)
 2639 
 2640     On platforms with tm_zone, strftime.c now assumes it is not NULL.
 2641     This simplifies the code and is consistent with zdump.c.
 2642     (Problem reported by Christos Zoulas.)
 2643 
 2644   Changes affecting documentation
 2645 
 2646    The tzfile man page now documents that transition times denote the
 2647    starts (not the ends) of the corresponding time periods.
 2648    (Ambiguity reported by Bill Seymour.)
 2649 
 2650 
 2651 Release 2015f - 2015-08-10 18:06:56 -0700
 2652 
 2653   Changes affecting future timestamps
 2654 
 2655     North Korea switches to +0830 on 2015-08-15.  (Thanks to Steffen Thorsen.)
 2656     The abbreviation remains "KST".  (Thanks to Robert Elz.)
 2657 
 2658     Uruguay no longer observes DST.  (Thanks to Steffen Thorsen
 2659     and Pablo Camargo.)
 2660 
 2661   Changes affecting past and future timestamps
 2662 
 2663     Moldova starts and ends DST at 00:00 UTC, not at 01:00 UTC.
 2664     (Thanks to Roman Tudos.)
 2665 
 2666   Changes affecting data format and code
 2667 
 2668     zic's '-y YEARISTYPE' option is no longer documented.  The TYPE
 2669     field of a Rule line should now be '-'; the old values 'even',
 2670     'odd', 'uspres', 'nonpres', 'nonuspres' were already undocumented.
 2671     Although the implementation has not changed, these features do not
 2672     work in the default installation, they are not used in the data,
 2673     and they are now considered obsolescent.
 2674 
 2675     zic now checks that two rules don't take effect at the same time.
 2676     (Thanks to Jon Skeet and Arthur David Olson.)  Constraints on
 2677     simultaneity are now documented.
 2678 
 2679     The two characters '%z' in a zone format now stand for the UT
 2680     offset, e.g., '-07' for seven hours behind UT and '+0530' for
 2681     five hours and thirty minutes ahead.  This better supports time
 2682     zone abbreviations conforming to POSIX.1-2001 and later.
 2683 
 2684   Changes affecting installed data files
 2685 
 2686     Comments for America/Halifax and America/Glace_Bay have been improved.
 2687     (Thanks to Brian Inglis.)
 2688 
 2689     Data entries have been simplified for Atlantic/Canary, Europe/Simferopol,
 2690     Europe/Sofia, and Europe/Tallinn.  This yields slightly smaller
 2691     installed data files for Europe/Simferopol and Europe/Tallinn.
 2692     It does not affect timestamps.  (Thanks to Howard Hinnant.)
 2693 
 2694   Changes affecting code
 2695 
 2696     zdump and zic no longer warn about valid time zone abbreviations
 2697     like '-05'.
 2698 
 2699     Some Visual Studio 2013 warnings have been suppressed.
 2700     (Thanks to Kees Dekker.)
 2701 
 2702     'date' no longer sets the time of day and its -a, -d, -n and -t
 2703     options have been removed.  Long obsolescent, the implementation
 2704     of these features had porting problems.  Builders no longer need
 2705     to configure HAVE_ADJTIME, HAVE_SETTIMEOFDAY, or HAVE_UTMPX_H.
 2706     (Thanks to Kees Dekker for pointing out the problem.)
 2707 
 2708   Changes affecting documentation
 2709 
 2710     The Theory file mentions naming issues earlier, as these seem to be
 2711     poorly publicized (thanks to Gilmore Davidson for reporting the problem).
 2712 
 2713     tz-link.htm mentions Time Zone Database Parser (thanks to Howard Hinnant).
 2714 
 2715     Mention that Herbert Samuel introduced the term "Summer Time".
 2716 
 2717 
 2718 Release 2015e - 2015-06-13 10:56:02 -0700
 2719 
 2720   Changes affecting future timestamps
 2721 
 2722     Morocco will suspend DST from 2015-06-14 03:00 through 2015-07-19 02:00,
 2723     not 06-13 and 07-18 as we had guessed.  (Thanks to Milamber.)
 2724 
 2725     Assume Cayman Islands will observe DST starting next year, using US rules.
 2726     Although it isn't guaranteed, it is the most likely.
 2727 
 2728   Changes affecting data format
 2729 
 2730     The file 'iso3166.tab' now uses UTF-8, so that its entries can better
 2731     spell the names of Åland Islands, Côte d'Ivoire, and Réunion.
 2732 
 2733   Changes affecting code
 2734 
 2735     When displaying data, tzselect converts it to the current locale's
 2736     encoding if the iconv command works.  (Problem reported by random832.)
 2737 
 2738     tzselect no longer mishandles Dominica, fixing a bug introduced
 2739     in Release 2014f.  (Problem reported by Owen Leibman.)
 2740 
 2741     zic -l no longer fails when compiled with -DTZDEFAULT=\"/etc/localtime\".
 2742     This fixes a bug introduced in Release 2014f.
 2743     (Problem reported by Leonardo Chiquitto.)
 2744 
 2745 
 2746 Release 2015d - 2015-04-24 08:09:46 -0700
 2747 
 2748   Changes affecting future timestamps
 2749 
 2750     Egypt will not observe DST in 2015 and will consider canceling it
 2751     permanently.  For now, assume no DST indefinitely.
 2752     (Thanks to Ahmed Nazmy and Tim Parenti.)
 2753 
 2754   Changes affecting past timestamps
 2755 
 2756     America/Whitehorse switched from UT -09 to -08 on 1967-05-28, not
 2757     1966-07-01.  Also, Yukon's time zone history is documented better.
 2758     (Thanks to Brian Inglis and Dennis Ferguson.)
 2759 
 2760   Change affecting past and future time zone abbreviations
 2761 
 2762     The abbreviations for Hawaii-Aleutian standard and daylight times
 2763     have been changed from HAST/HADT to HST/HDT, as per US Government
 2764     Printing Office style.  This affects only America/Adak since 1983,
 2765     as America/Honolulu was already using the new style.
 2766 
 2767   Changes affecting code
 2768 
 2769    zic has some minor performance improvements.
 2770 
 2771 
 2772 Release 2015c - 2015-04-11 08:55:55 -0700
 2773 
 2774   Changes affecting future timestamps
 2775 
 2776     Egypt's spring-forward transition is at 24:00 on April's last Thursday,
 2777     not 00:00 on April's last Friday.  2015's transition will therefore be on
 2778     Thursday, April 30 at 24:00, not Friday, April 24 at 00:00.  Similar fixes
 2779     apply to 2026, 2037, 2043, etc.  (Thanks to Steffen Thorsen.)
 2780 
 2781   Changes affecting past timestamps
 2782 
 2783     The following changes affect some pre-1991 Chile-related timestamps
 2784     in America/Santiago, Antarctica/Palmer, and Pacific/Easter.
 2785 
 2786       The 1910 transition was January 10, not January 1.
 2787 
 2788       The 1918 transition was September 10, not September 1.
 2789 
 2790       The UT -04 time observed from 1932 to 1942 is now considered to
 2791       be standard time, not year-round DST.
 2792 
 2793       Santiago observed DST (UT -03) from 1946-07-15 through
 2794       1946-08-31, then reverted to standard time, then switched to -05
 2795       on 1947-04-01.
 2796 
 2797       Assume transitions before 1968 were at 00:00, since we have no data
 2798       saying otherwise.
 2799 
 2800       The spring 1988 transition was 1988-10-09, not 1988-10-02.
 2801       The fall 1990 transition was 1990-03-11, not 1990-03-18.
 2802 
 2803       Assume no UT offset change for Pacific/Easter on 1890-01-01,
 2804       and omit all transitions on Pacific/Easter from 1942 through 1946
 2805       since we have no data suggesting that they existed.
 2806 
 2807     One more zone has been turned into a link, as it differed
 2808     from an existing zone only for older timestamps.  As usual,
 2809     this change affects UT offsets in pre-1970 timestamps only.
 2810     The zone's old contents have been moved to the 'backzone' file.
 2811     The affected zone is America/Montreal.
 2812 
 2813   Changes affecting commentary
 2814 
 2815     Mention the TZUpdater tool.
 2816 
 2817     Mention "The Time Now".  (Thanks to Brandon Ramsey.)
 2818 
 2819 
 2820 Release 2015b - 2015-03-19 23:28:11 -0700
 2821 
 2822   Changes affecting future timestamps
 2823 
 2824     Mongolia will start observing DST again this year, from the last
 2825     Saturday in March at 02:00 to the last Saturday in September at 00:00.
 2826     (Thanks to Ganbold Tsagaankhuu.)
 2827 
 2828     Palestine will start DST on March 28, not March 27.  Also,
 2829     correct the fall 2014 transition from September 26 to October 24.
 2830     Adjust future predictions accordingly.  (Thanks to Steffen Thorsen.)
 2831 
 2832   Changes affecting past timestamps
 2833 
 2834     The 1982 zone shift in Pacific/Easter has been corrected, fixing a 2015a
 2835     regression.  (Thanks to Stuart Bishop for reporting the problem.)
 2836 
 2837     Some more zones have been turned into links, when they differed
 2838     from existing zones only for older timestamps.  As usual,
 2839     these changes affect UT offsets in pre-1970 timestamps only.
 2840     Their old contents have been moved to the 'backzone' file.
 2841     The affected zones are: America/Antigua, America/Cayman,
 2842     Pacific/Midway, and Pacific/Saipan.
 2843 
 2844   Changes affecting time zone abbreviations
 2845 
 2846     Correct the 1992-2010 DST abbreviation in Volgograd from "MSK" to "MSD".
 2847     (Thanks to Hank W.)
 2848 
 2849   Changes affecting code
 2850 
 2851     Fix integer overflow bug in reference 'mktime' implementation.
 2852     (Problem reported by Jörg Richter.)
 2853 
 2854     Allow -Dtime_tz=time_t compilations, and allow -Dtime_tz=... libraries
 2855     to be used in the same executable as standard-library time_t functions.
 2856     (Problems reported by Bradley White.)
 2857 
 2858   Changes affecting commentary
 2859 
 2860     Cite the recent Mexican decree changing Quintana Roo's time zone.
 2861     (Thanks to Carlos Raúl Perasso.)
 2862 
 2863     Likewise for the recent Chilean decree.  (Thanks to Eduardo Romero Urra.)
 2864 
 2865     Update info about Mars time.
 2866 
 2867 
 2868 Release 2015a - 2015-01-29 22:35:20 -0800
 2869 
 2870   Changes affecting future timestamps
 2871 
 2872     The Mexican state of Quintana Roo, represented by America/Cancun,
 2873     will shift from Central Time with DST to Eastern Time without DST
 2874     on 2015-02-01 at 02:00.  (Thanks to Steffen Thorsen and Gwillim Law.)
 2875 
 2876     Chile will not change clocks in April or thereafter; its new standard time
 2877     will be its old daylight saving time.  This affects America/Santiago,
 2878     Pacific/Easter, and Antarctica/Palmer.  (Thanks to Juan Correa.)
 2879 
 2880     New leap second 2015-06-30 23:59:60 UTC as per IERS Bulletin C 49.
 2881     (Thanks to Tim Parenti.)
 2882 
 2883   Changes affecting past timestamps
 2884 
 2885     Iceland observed DST in 1919 and 1921, and its 1939 fallback
 2886     transition was Oct. 29, not Nov. 29.  Remove incorrect data from
 2887     Shanks about time in Iceland between 1837 and 1908.
 2888 
 2889     Some more zones have been turned into links, when they differed
 2890     from existing zones only for older timestamps.  As usual,
 2891     these changes affect UT offsets in pre-1970 timestamps only.
 2892     Their old contents have been moved to the 'backzone' file.
 2893     The affected zones are: Asia/Aden, Asia/Bahrain, Asia/Kuwait,
 2894     and Asia/Muscat.
 2895 
 2896   Changes affecting code
 2897 
 2898     tzalloc now scrubs time zone abbreviations compatibly with the way
 2899     that tzset always has, by replacing invalid bytes with '_' and by
 2900     shortening too-long abbreviations.
 2901 
 2902     tzselect ports to POSIX awk implementations, no longer mishandles
 2903     POSIX TZ settings when GNU awk is used, and reports POSIX TZ
 2904     settings to the user.  (Thanks to Stefan Kuhn.)
 2905 
 2906   Changes affecting build procedure
 2907 
 2908     'make check' now checks for links to links in the data.
 2909     One such link (for Africa/Asmera) has been fixed.
 2910     (Thanks to Stephen Colebourne for pointing out the problem.)
 2911 
 2912   Changes affecting commentary
 2913 
 2914     The leapseconds file commentary now mentions the expiration date.
 2915     (Problem reported by Martin Burnicki.)
 2916 
 2917     Update Mexican Library of Congress URL.
 2918 
 2919 
 2920 Release 2014j - 2014-11-10 17:37:11 -0800
 2921 
 2922   Changes affecting current and future timestamps
 2923 
 2924     Turks & Caicos' switch from US eastern time to UT -04 year-round
 2925     did not occur on 2014-11-02 at 02:00.  It's currently scheduled
 2926     for 2015-11-01 at 02:00.  (Thanks to Chris Walton.)
 2927 
 2928   Changes affecting past timestamps
 2929 
 2930     Many pre-1989 timestamps have been corrected for Asia/Seoul and
 2931     Asia/Pyongyang, based on sources for the Korean-language Wikipedia
 2932     entry for time in Korea.  (Thanks to Sanghyuk Jung.)  Also, no
 2933     longer guess that Pyongyang mimicked Seoul time after World War II,
 2934     as this is politically implausible.
 2935 
 2936     Some more zones have been turned into links, when they differed
 2937     from existing zones only for older timestamps.  As usual,
 2938     these changes affect UT offsets in pre-1970 timestamps only.
 2939     Their old contents have been moved to the 'backzone' file.
 2940     The affected zones are: Africa/Addis_Ababa, Africa/Asmara,
 2941     Africa/Dar_es_Salaam, Africa/Djibouti, Africa/Kampala,
 2942     Africa/Mogadishu, Indian/Antananarivo, Indian/Comoro, and
 2943     Indian/Mayotte.
 2944 
 2945   Changes affecting commentary
 2946 
 2947     The commentary is less enthusiastic about Shanks as a source,
 2948     and is more careful to distinguish UT from UTC.
 2949 
 2950 
 2951 Release 2014i - 2014-10-21 22:04:57 -0700
 2952 
 2953   Changes affecting future timestamps
 2954 
 2955     Pacific/Fiji will observe DST from 2014-11-02 02:00 to 2015-01-18 03:00.
 2956     (Thanks to Ken Rylander for the heads-up.)  Guess that future
 2957     years will use a similar pattern.
 2958 
 2959     A new Zone Pacific/Bougainville, for the part of Papua New Guinea
 2960     that plans to switch from UT +10 to +11 on 2014-12-28 at 02:00.
 2961     (Thanks to Kiley Walbom for the heads-up.)
 2962 
 2963   Changes affecting time zone abbreviations
 2964 
 2965     Since Belarus is not changing its clocks even though Moscow is,
 2966     the time zone abbreviation in Europe/Minsk is changing from FET
 2967     to its more-traditional value MSK on 2014-10-26 at 01:00.
 2968     (Thanks to Alexander Bokovoy for the heads-up about Belarus.)
 2969 
 2970     The new abbreviation IDT stands for the pre-1976 use of UT +08 in
 2971     Indochina, to distinguish it better from ICT (+07).
 2972 
 2973   Changes affecting past timestamps
 2974 
 2975     Many timestamps have been corrected for Asia/Ho_Chi_Minh before 1976
 2976     (thanks to Trần Ngọc Quân for an indirect pointer to Trần Tiến Bình's
 2977     authoritative book).  Asia/Ho_Chi_Minh has been added to
 2978     zone1970.tab, to give tzselect users in Vietnam two choices,
 2979     since north and south Vietnam disagreed after our 1970 cutoff.
 2980 
 2981     Asia/Phnom_Penh and Asia/Vientiane have been turned into links, as
 2982     they differed from existing zones only for older timestamps.  As
 2983     usual, these changes affect pre-1970 timestamps only.  Their old
 2984     contents have been moved to the 'backzone' file.
 2985 
 2986   Changes affecting code
 2987 
 2988     The time-related library functions now set errno on failure, and
 2989     some crashes in the new tzalloc-related library functions have
 2990     been fixed.  (Thanks to Christos Zoulas for reporting most of
 2991     these problems and for suggesting fixes.)
 2992 
 2993     If USG_COMPAT is defined and the requested timestamp is standard time,
 2994     the tz library's localtime and mktime functions now set the extern
 2995     variable timezone to a value appropriate for that timestamp; and
 2996     similarly for ALTZONE, daylight saving time, and the altzone variable.
 2997     This change is a companion to the tzname change in 2014h, and is
 2998     designed to make timezone and altzone more compatible with tzname.
 2999 
 3000     The tz library's functions now set errno to EOVERFLOW if they fail
 3001     because the result cannot be represented.  ctime and ctime_r now
 3002     return NULL and set errno when a timestamp is out of range, rather
 3003     than having undefined behavior.
 3004 
 3005     Some bugs associated with the new 2014g functions have been fixed.
 3006     This includes a bug that largely incapacitated the new functions
 3007     time2posix_z and posix2time_z.  (Thanks to Christos Zoulas.)
 3008     It also includes some uses of uninitialized variables after tzalloc.
 3009     The new code uses the standard type 'ssize_t', which the Makefile
 3010     now gives porting advice about.
 3011 
 3012   Changes affecting commentary
 3013 
 3014     Updated URLs for NRC Canada (thanks to Matt Johnson and Brian Inglis).
 3015 
 3016 
 3017 Release 2014h - 2014-09-25 18:59:03 -0700
 3018 
 3019   Changes affecting past timestamps
 3020 
 3021     America/Jamaica's 1974 spring-forward transition was Jan. 6, not Apr. 28.
 3022 
 3023     Shanks says Asia/Novokuznetsk switched from LMT (not "NMT") on 1924-05-01,
 3024     not 1920-01-06.  The old entry was based on a misinterpretation of Shanks.
 3025 
 3026     Some more zones have been turned into links, when they differed
 3027     from existing zones only for older timestamps.  As usual,
 3028     these changes affect UT offsets in pre-1970 timestamps only.
 3029     Their old contents have been moved to the 'backzone' file.
 3030     The affected zones are: Africa/Blantyre, Africa/Bujumbura,
 3031     Africa/Gaborone, Africa/Harare, Africa/Kigali, Africa/Lubumbashi,
 3032     Africa/Lusaka, Africa/Maseru, and Africa/Mbabane.
 3033 
 3034   Changes affecting code
 3035 
 3036     zdump -V and -v now output gmtoff= values on all platforms,
 3037     not merely on platforms defining TM_GMTOFF.
 3038 
 3039     The tz library's localtime and mktime functions now set tzname to a value
 3040     appropriate for the requested timestamp, and zdump now uses this
 3041     on platforms not defining TM_ZONE, fixing a 2014g regression.
 3042     (Thanks to Tim Parenti for reporting the problem.)
 3043 
 3044     The tz library no longer sets tzname if localtime or mktime fails.
 3045 
 3046     zdump -c no longer mishandles transitions near year boundaries.
 3047     (Thanks to Tim Parenti for reporting the problem.)
 3048 
 3049     An access to uninitialized data has been fixed.
 3050     (Thanks to Jörg Richter for reporting the problem.)
 3051 
 3052     When THREAD_SAFE is defined, the code ports to the C11 memory model.
 3053     A memory leak has been fixed if ALL_STATE and THREAD_SAFE are defined
 3054     and two threads race to initialize data used by gmtime-like functions.
 3055     (Thanks to Andy Heninger for reporting the problems.)
 3056 
 3057   Changes affecting build procedure
 3058 
 3059     'make check' now checks better for properly-sorted data.
 3060 
 3061   Changes affecting documentation and commentary
 3062 
 3063     zdump's gmtoff=N output is now documented, and its isdst=D output
 3064     is now documented to possibly output D values other than 0 or 1.
 3065 
 3066     zdump -c's treatment of years is now documented to use the
 3067     Gregorian calendar and Universal Time without leap seconds,
 3068     and its behavior at cutoff boundaries is now documented better.
 3069     (Thanks to Arthur David Olson and Tim Parenti for reporting the problems.)
 3070 
 3071     Programs are now documented to use the proleptic Gregorian calendar.
 3072     (Thanks to Alan Barrett for the suggestion.)
 3073 
 3074     Fractional-second GMT offsets have been documented for civil time
 3075     in 19th-century Chennai, Jakarta, and New York.
 3076 
 3077 
 3078 Release 2014g - 2014-08-28 12:31:23 -0700
 3079 
 3080   Changes affecting future timestamps
 3081 
 3082     Turks & Caicos is switching from US eastern time to UT -04
 3083     year-round, modeled as a switch on 2014-11-02 at 02:00.
 3084     [As noted in 2014j, this switch was later delayed.]
 3085 
 3086   Changes affecting past timestamps
 3087 
 3088     Time in Russia or the USSR before 1926 or so has been corrected by
 3089     a few seconds in the following zones: Asia/Irkutsk,
 3090     Asia/Krasnoyarsk, Asia/Omsk, Asia/Samarkand, Asia/Tbilisi,
 3091     Asia/Vladivostok, Asia/Yakutsk, Europe/Riga, Europe/Samara.  For
 3092     Asia/Yekaterinburg the correction is a few minutes.  (Thanks to
 3093     Vladimir Karpinsky.)
 3094 
 3095     The Portuguese decree of 1911-05-26 took effect on 1912-01-01.
 3096     This affects 1911 timestamps in Africa/Bissau, Africa/Luanda,
 3097     Atlantic/Azores, and Atlantic/Madeira.  Also, Lisbon's pre-1912
 3098     GMT offset was -0:36:45 (rounded from -0:36:44.68), not -0:36:32.
 3099     (Thanks to Stephen Colebourne for pointing to the decree.)
 3100 
 3101     Asia/Dhaka ended DST on 2009-12-31 at 24:00, not 23:59.
 3102 
 3103     A new file 'backzone' contains data which may appeal to
 3104     connoisseurs of old timestamps, although it is out of scope for
 3105     the tz database, is often poorly sourced, and contains some data
 3106     that is known to be incorrect.  The new file is not recommended
 3107     for ordinary use and its entries are not installed by default.
 3108     (Thanks to Lester Caine for the high-quality Jersey, Guernsey, and
 3109     Isle of Man entries.)
 3110 
 3111     Some more zones have been turned into links, when they differed
 3112     from existing zones only for older timestamps.  As usual,
 3113     these changes affect UT offsets in pre-1970 timestamps only.
 3114     Their old contents have been moved to the 'backzone' file.
 3115     The affected zones are: Africa/Bangui, Africa/Brazzaville,
 3116     Africa/Douala, Africa/Kinshasa, Africa/Libreville, Africa/Luanda,
 3117     Africa/Malabo, Africa/Niamey, and Africa/Porto-Novo.
 3118 
 3119   Changes affecting code
 3120 
 3121     Unless NETBSD_INSPIRED is defined to 0, the tz library now
 3122     supplies functions for creating and using objects that represent
 3123     timezones. The new functions are tzalloc, tzfree, localtime_rz,
 3124     mktime_z, and (if STD_INSPIRED is also defined) posix2time_z and
 3125     time2posix_z.  They are intended for performance: for example,
 3126     localtime_rz (unlike localtime_r) is trivially thread-safe without
 3127     locking.  (Thanks to Christos Zoulas for proposing NetBSD-inspired
 3128     functions, and to Alan Barrett and Jonathan Lennox for helping to
 3129     debug the change.)
 3130 
 3131     zdump now builds with the tz library unless USE_LTZ is defined to 0,
 3132     This lets zdump use tz features even if the system library lacks them.
 3133     To build zdump with the system library, use 'make CFLAGS=-DUSE_LTZ=0
 3134     TZDOBJS=zdump.o CHECK_TIME_T_ALTERNATIVES='.
 3135 
 3136     zdump now uses localtime_rz if available, as it's significantly faster,
 3137     and it can help zdump better diagnose invalid timezone names.
 3138     Define HAVE_LOCALTIME_RZ to 0 to suppress this.  HAVE_LOCALTIME_RZ
 3139     defaults to 1 if NETBSD_INSPIRED && USE_LTZ.  When localtime_rz is
 3140     not available, zdump now uses localtime_r and tzset if available,
 3141     as this is a bit cleaner and faster than plain localtime.  Compile
 3142     with -DHAVE_LOCALTIME_R=0 and/or -DHAVE_TZSET=0 if your system
 3143     lacks these two functions.
 3144 
 3145     If THREAD_SAFE is defined to 1, the tz library is now thread-safe.
 3146     Although not needed for tz's own applications, which are single-threaded,
 3147     this supports POSIX better if the tz library is used in multithreaded apps.
 3148 
 3149     Some crashes have been fixed when zdump or the tz library is given
 3150     invalid or outlandish input.
 3151 
 3152     The tz library no longer mishandles leap seconds on platforms with
 3153     unsigned time_t in timezones that lack ordinary transitions after 1970.
 3154 
 3155     The tz code now attempts to infer TM_GMTOFF and TM_ZONE if not
 3156     already defined, to make it easier to configure on common platforms.
 3157     Define NO_TM_GMTOFF and NO_TM_ZONE to suppress this.
 3158 
 3159     Unless the new macro UNINIT_TRAP is defined to 1, the tz code now
 3160     assumes that reading uninitialized memory yields garbage values
 3161     but does not cause other problems such as traps.
 3162 
 3163     If TM_GMTOFF is defined and UNINIT_TRAP is 0, mktime is now
 3164     more likely to guess right for ambiguous timestamps near
 3165     transitions where tm_isdst does not change.
 3166 
 3167     If HAVE_STRFTIME_L is defined to 1, the tz library now defines
 3168     strftime_l for compatibility with recent versions of POSIX.
 3169     Only the C locale is supported, though.  HAVE_STRFTIME_L defaults
 3170     to 1 on recent POSIX versions, and to 0 otherwise.
 3171 
 3172     tzselect -c now uses a hybrid distance measure that works better
 3173     in Africa.  (Thanks to Alan Barrett for noting the problem.)
 3174 
 3175     The C source code now ports to NetBSD when GCC_DEBUG_FLAGS is used,
 3176     or when time_tz is defined.
 3177 
 3178     When HAVE_UTMPX_H is set the 'date' command now builds on systems
 3179     whose <utmpx.h> file does not define WTMPX_FILE, and when setting
 3180     the date it updates the wtmpx file if _PATH_WTMPX is defined.
 3181     This affects GNU/Linux and similar systems.
 3182 
 3183     For easier maintenance later, some C code has been simplified,
 3184     some lint has been removed, and the code has been tweaked so that
 3185     plain 'make' is more likely to work.
 3186 
 3187     The C type 'bool' is now used for boolean values, instead of 'int'.
 3188 
 3189     The long-obsolete LOCALE_HOME code has been removed.
 3190 
 3191     The long-obsolete 'gtime' function has been removed.
 3192 
 3193   Changes affecting build procedure
 3194 
 3195     'zdump' no longer links in ialloc.o, as it's not needed.
 3196 
 3197     'make check_time_t_alternatives' no longer assumes GNU diff.
 3198 
 3199   Changes affecting distribution tarballs
 3200 
 3201     The files checktab.awk and zoneinfo2tdf.pl are now distributed in
 3202     the tzdata tarball instead of the tzcode tarball, since they help
 3203     maintain the data.  The NEWS and Theory files are now also
 3204     distributed in the tzdata tarball, as they're relevant for data.
 3205     (Thanks to Alan Barrett for pointing this out.)  Also, the
 3206     leapseconds.awk file is no longer distributed in the tzcode
 3207     tarball, since it belongs in the tzdata tarball (where 2014f
 3208     inadvertently also distributed it).
 3209 
 3210   Changes affecting documentation and commentary
 3211 
 3212     A new file CONTRIBUTING is distributed.  (Thanks to Tim Parenti for
 3213     suggesting a CONTRIBUTING file, and to Tony Finch and Walter Harms
 3214     for debugging it.)
 3215 
 3216     The man pages have been updated to use function prototypes,
 3217     to document thread-safe variants like localtime_r, and to document
 3218     the NetBSD-inspired functions tzalloc, tzfree, localtime_rz, and
 3219     mktime_z.
 3220 
 3221     The fields in Link lines have been renamed to be more descriptive
 3222     and more like the parameters of 'ln'.  LINK-FROM has become TARGET,
 3223     and LINK-TO has become LINK-NAME.
 3224 
 3225     tz-link.htm mentions the IETF's tzdist working group; Windows
 3226     Runtime etc. (thanks to Matt Johnson); and HP-UX's tztab.
 3227 
 3228     Some broken URLs have been fixed in the commentary.  (Thanks to
 3229     Lester Caine.)
 3230 
 3231     Commentary about Philippines DST has been updated, and commentary
 3232     on pre-1970 time in India has been added.
 3233 
 3234 
 3235 Release 2014f - 2014-08-05 17:42:36 -0700
 3236 
 3237   Changes affecting future timestamps
 3238 
 3239     Russia will subtract an hour from most of its time zones on 2014-10-26
 3240     at 02:00 local time.  (Thanks to Alexander Krivenyshev.)
 3241     There are a few exceptions: Magadan Oblast (Asia/Magadan) and Zabaykalsky
 3242     Krai are subtracting two hours; conversely, Chukotka Autonomous Okrug
 3243     (Asia/Anadyr), Kamchatka Krai (Asia/Kamchatka), Kemerovo Oblast
 3244     (Asia/Novokuznetsk), and the Samara Oblast and the Udmurt Republic
 3245     (Europe/Samara) are not changing their clocks.  The changed zones are
 3246     Europe/Kaliningrad, Europe/Moscow, Europe/Simferopol, Europe/Volgograd,
 3247     Asia/Yekaterinburg, Asia/Omsk, Asia/Novosibirsk, Asia/Krasnoyarsk,
 3248     Asia/Irkutsk, Asia/Yakutsk, Asia/Vladivostok, Asia/Khandyga,
 3249     Asia/Sakhalin, and Asia/Ust-Nera; Asia/Magadan will have two hours
 3250     subtracted; and Asia/Novokuznetsk's time zone abbreviation is affected,
 3251     but not its UTC offset.  Two zones are added: Asia/Chita (split
 3252     from Asia/Yakutsk, and also with two hours subtracted) and
 3253     Asia/Srednekolymsk (split from Asia/Magadan, but with only one hour
 3254     subtracted).  (Thanks to Tim Parenti for much of the above.)
 3255 
 3256   Changes affecting time zone abbreviations
 3257 
 3258     Australian eastern time zone abbreviations are now AEST/AEDT not EST,
 3259     and similarly for the other Australian zones.  That is, for eastern
 3260     standard and daylight saving time the abbreviations are AEST and AEDT
 3261     instead of the former EST for both; similarly, ACST/ACDT, ACWST/ACWDT,
 3262     and AWST/AWDT are now used instead of the former CST, CWST, and WST.
 3263     This change does not affect UT offsets, only time zone abbreviations.
 3264     (Thanks to Rich Tibbett and many others.)
 3265 
 3266     Asia/Novokuznetsk shifts from NOVT to KRAT (remaining on UT +07)
 3267     effective 2014-10-26 at 02:00 local time.
 3268 
 3269     The time zone abbreviation for Xinjiang Time (observed in Ürümqi)
 3270     has been changed from URUT to XJT.  (Thanks to Luther Ma.)
 3271 
 3272     Prefer MSK/MSD for Moscow time in Russia, even in other cities.
 3273     Similarly, prefer EET/EEST for eastern European time in Russia.
 3274 
 3275     Change time zone abbreviations in (western) Samoa to use "ST" and
 3276     "DT" suffixes, as this is more likely to match common practice.
 3277     Prefix "W" to (western) Samoa time when its standard-time offset
 3278     disagrees with that of American Samoa.
 3279 
 3280     America/Metlakatla now uses PST, not MeST, to abbreviate its time zone.
 3281 
 3282     Time zone abbreviations have been updated for Japan's two time
 3283     zones used 1896-1937.  JWST now stands for Western Standard
 3284     Time, and JCST for Central Standard Time (formerly this was CJT).
 3285     These abbreviations are now used for time in Korea, Taiwan,
 3286     and Sakhalin while controlled by Japan.
 3287 
 3288   Changes affecting past timestamps
 3289 
 3290     China's five zones have been simplified to two, since the post-1970
 3291     differences in the other three seem to have been imaginary.  The
 3292     zones Asia/Harbin, Asia/Chongqing, and Asia/Kashgar have been
 3293     removed; backwards-compatibility links still work, albeit with
 3294     different behaviors for timestamps before May 1980.  Asia/Urumqi's
 3295     1980 transition to UT +08 has been removed, so that it is now at
 3296     +06 and not +08.  (Thanks to Luther Ma and to Alois Treindl;
 3297     Treindl sent helpful translations of two papers by Guo Qingsheng.)
 3298 
 3299     Some zones have been turned into links, when they differed from existing
 3300     zones only for older UT offsets where data entries were likely invented.
 3301     These changes affect UT offsets in pre-1970 timestamps only.  This is
 3302     similar to the change in release 2013e, except this time for western
 3303     Africa.  The affected zones are: Africa/Bamako, Africa/Banjul,
 3304     Africa/Conakry, Africa/Dakar, Africa/Freetown, Africa/Lome,
 3305     Africa/Nouakchott, Africa/Ouagadougou, Africa/Sao_Tome, and
 3306     Atlantic/St_Helena.  This also affects the backwards-compatibility
 3307     link Africa/Timbuktu.  (Thanks to Alan Barrett, Stephen Colebourne,
 3308     Tim Parenti, and David Patte for reporting problems in earlier
 3309     versions of this change.)
 3310 
 3311     Asia/Shanghai's pre-standard-time UT offset has been changed from
 3312     8:05:57 to 8:05:43, the location of Xujiahui Observatory.  Its
 3313     transition to standard time has been changed from 1928 to 1901.
 3314 
 3315     Asia/Taipei switched to JWST on 1896-01-01, then to JST on 1937-10-01,
 3316     then to CST on 1945-09-21 at 01:00, and did not observe DST in 1945.
 3317     In 1946 it observed DST from 05-15 through 09-30; in 1947
 3318     from 04-15 through 10-31; and in 1979 from 07-01 through 09-30.
 3319     (Thanks to Yu-Cheng Chuang.)
 3320 
 3321     Asia/Riyadh's transition to standard time is now 1947-03-14, not 1950.
 3322 
 3323     Europe/Helsinki's 1942 fall-back transition was 10-04 at 01:00, not
 3324     10-03 at 00:00.  (Thanks to Konstantin Hyppönen.)
 3325 
 3326     Pacific/Pago_Pago has been changed from UT -11:30 to -11 for the
 3327     period from 1911 to 1950.
 3328 
 3329     Pacific/Chatham has been changed to New Zealand standard time plus
 3330     45 minutes for the period before 1957, reflecting a 1956 remark in
 3331     the New Zealand parliament.
 3332 
 3333     Europe/Budapest has several pre-1946 corrections: in 1918 the transition
 3334     out of DST was on 09-16, not 09-29; in 1919 it was on 11-24, not 09-15; in
 3335     1945 it was on 11-01, not 11-03; in 1941 the transition to DST was 04-08
 3336     not 04-06 at 02:00; and there was no DST in 1920.
 3337 
 3338     Africa/Accra is now assumed to have observed DST from 1920 through 1935.
 3339 
 3340     Time in Russia before 1927 or so has been corrected by a few seconds in
 3341     the following zones: Europe/Moscow, Asia/Irkutsk, Asia/Tbilisi,
 3342     Asia/Tashkent, Asia/Vladivostok, Asia/Yekaterinburg, Europe/Helsinki, and
 3343     Europe/Riga.  Also, Moscow's location has been changed to its Kilometer 0
 3344     point.  (Thanks to Vladimir Karpinsky for the Moscow changes.)
 3345 
 3346   Changes affecting data format
 3347 
 3348     A new file 'zone1970.tab' supersedes 'zone.tab' in the installed data.
 3349     The new file's extended format allows multiple country codes per zone.
 3350     The older file is still installed but is deprecated; its format is
 3351     not changing and it will still be distributed for a while, but new
 3352     applications should use the new file.
 3353 
 3354     The new file format simplifies maintenance of obscure locations.
 3355     To test this, it adds coverage for the Crozet Islands and the
 3356     Scattered Islands.  (Thanks to Tobias Conradi and Antoine Leca.)
 3357 
 3358     The file 'iso3166.tab' is planned to switch from ASCII to UTF-8.
 3359     It is still ASCII now, but commentary about the switch has been added.
 3360     The new file 'zone1970.tab' already uses UTF-8.
 3361 
 3362   Changes affecting code
 3363 
 3364     'localtime', 'mktime', etc. now use much less stack space if ALL_STATE
 3365     is defined.  (Thanks to Elliott Hughes for reporting the problem.)
 3366 
 3367     'zic' no longer mishandles input when ignoring case in locales that
 3368     are not compatible with English, e.g., unibyte Turkish locales when
 3369     compiled with HAVE_GETTEXT.
 3370 
 3371     Error diagnostics of 'zic' and 'yearistype' have been reworded so that
 3372     they no longer use ASCII '-' as if it were a dash.
 3373 
 3374     'zic' now rejects output file names that contain '.' or '..' components.
 3375     (Thanks to Tim Parenti for reporting the problem.)
 3376 
 3377     'zic -v' now warns about output file names that do not follow
 3378     POSIX rules, or that contain a digit or '.'.  (Thanks to Arthur
 3379     David Olson for starting the ball rolling on this.)
 3380 
 3381     Some lint has been removed when using GCC_DEBUG_FLAGS with GCC 4.9.0.
 3382 
 3383   Changes affecting build procedure
 3384 
 3385     'zic' no longer links in localtime.o and asctime.o, as they're not needed.
 3386     (Thanks to John Cochran.)
 3387 
 3388   Changes affecting documentation and commentary
 3389 
 3390     The 'Theory' file documents legacy names, the longstanding
 3391     exceptions to the POSIX-inspired file name rules.
 3392 
 3393     The 'zic' documentation clarifies the role of time types when
 3394     interpreting dates.  (Thanks to Arthur David Olson.)
 3395 
 3396     Documentation and commentary now prefer UTF-8 to US-ASCII,
 3397     allowing the use of proper accents in foreign words and names.
 3398     Code and data have not changed because of this.  (Thanks to
 3399     Garrett Wollman, Ian Abbott, and Guy Harris for helping to debug
 3400     this.)
 3401 
 3402     Non-HTML documentation and commentary now use plain-text URLs instead of
 3403     HTML insertions, and are more consistent about bracketing URLs when they
 3404     are not already surrounded by white space.  (Thanks to suggestions by
 3405     Steffen Nurpmeso.)
 3406 
 3407     There is new commentary about Xujiahui Observatory, the five time-zone
 3408     project in China from 1918 to 1949, timekeeping in Japanese-occupied
 3409     Shanghai, and Tibet Time in the 1950s.  The sharp-eyed can spot the
 3410     warlord Jin Shuren in the data.
 3411 
 3412     Commentary about the coverage of each Russian zone has been standardized.
 3413     (Thanks to Tim Parenti.)
 3414 
 3415     There is new commentary about contemporary timekeeping in Ethiopia.
 3416 
 3417     Obsolete comments about a 2007 proposal for DST in Kuwait has been removed.
 3418 
 3419     There is new commentary about time in Poland in 1919.
 3420 
 3421     Proper credit has been given to DST inventor George Vernon Hudson.
 3422 
 3423     Commentary about time in Metlakatla, AK and Resolute, NU has been
 3424     improved, with a new source for the former.
 3425 
 3426     In zone.tab, Pacific/Easter no longer mentions Salas y Gómez, as it
 3427     is uninhabited.
 3428 
 3429     Commentary about permanent Antarctic bases has been updated.
 3430 
 3431     Several typos have been corrected.  (Thanks to Tim Parenti for
 3432     contributing some of these fixes.)
 3433 
 3434     tz-link.htm now mentions the JavaScript libraries Moment Timezone,
 3435     TimezoneJS.Date, Walltime-js, and Timezone.  (Thanks to a heads-up
 3436     from Matt Johnson.)  Also, it mentions the Go 'latlong' package.
 3437     (Thanks to a heads-up from Dirkjan Ochtman.)
 3438 
 3439     The files usno1988, usno1989, usno1989a, usno1995, usno1997, and usno1998
 3440     have been removed.  These obsolescent US Naval Observatory entries were no
 3441     longer helpful for maintenance.  (Thanks to Tim Parenti for the suggestion.)
 3442 
 3443 
 3444 Release 2014e - 2014-06-12 21:53:52 -0700
 3445 
 3446   Changes affecting near-future timestamps
 3447 
 3448     Egypt's 2014 Ramadan-based transitions are June 26 and July 31 at 24:00.
 3449     (Thanks to Imed Chihi.)  Guess that from 2015 on Egypt will temporarily
 3450     switch to standard time at 24:00 the last Thursday before Ramadan, and
 3451     back to DST at 00:00 the first Friday after Ramadan.
 3452 
 3453     Similarly, Morocco's are June 28 at 03:00 and August 2 at 02:00.  (Thanks
 3454     to Milamber Space Network.)  Guess that from 2015 on Morocco will
 3455     temporarily switch to standard time at 03:00 the last Saturday before
 3456     Ramadan, and back to DST at 02:00 the first Saturday after Ramadan.
 3457 
 3458   Changes affecting past timestamps
 3459 
 3460     The abbreviation "MSM" (Moscow Midsummer Time) is now used instead of
 3461     "MSD" for Moscow's double daylight time in summer 1921.  Also, a typo
 3462     "VLASST" has been repaired to be "VLAST" for Vladivostok summer time
 3463     in 1991.  (Thanks to Hank W. for reporting the problems.)
 3464 
 3465   Changes affecting commentary
 3466 
 3467     tz-link.htm now cites RFC 7265 for jCal, mentions PTP and the
 3468     draft CalDAV extension, updates URLs for TSP, TZInfo, IATA, and
 3469     removes stale pointers to World Time Explorer and WORLDTIME.
 3470 
 3471 
 3472 Release 2014d - 2014-05-27 21:34:40 -0700
 3473 
 3474   Changes affecting code
 3475 
 3476     zic no longer generates files containing timestamps before the Big Bang.
 3477     This works around GNOME glib bug 878
 3478     <https://gitlab.gnome.org/GNOME/glib/issues/878>
 3479     (Thanks to Leonardo Chiquitto for reporting the bug, and to
 3480     Arthur David Olson and James Cloos for suggesting improvements to the fix.)
 3481 
 3482   Changes affecting documentation
 3483 
 3484     tz-link.htm now mentions GNOME.
 3485 
 3486 
 3487 Release 2014c - 2014-05-13 07:44:13 -0700
 3488 
 3489   Changes affecting near-future timestamps
 3490 
 3491     Egypt observes DST starting 2014-05-15 at 24:00.
 3492     (Thanks to Ahmad El-Dardiry and Gunther Vermier.)
 3493     Details have not been announced, except that DST will not be observed
 3494     during Ramadan.  Guess that DST will stop during the same Ramadan dates as
 3495     Morocco, and that Egypt's future spring and fall transitions will be the
 3496     same as 2010 when it last observed DST, namely April's last Friday at
 3497     00:00 to September's last Thursday at 23:00 standard time.  Also, guess
 3498     that Ramadan transitions will be at 00:00 standard time.
 3499 
 3500   Changes affecting code
 3501 
 3502     zic now generates transitions for minimum time values, eliminating guesswork
 3503     when handling low-valued timestamps.  (Thanks to Arthur David Olson.)
 3504 
 3505     Port to Cygwin sans glibc.  (Thanks to Arthur David Olson.)
 3506 
 3507   Changes affecting commentary and documentation
 3508 
 3509     Remove now-confusing comment about Jordan.  (Thanks to Oleksii Nochovnyi.)
 3510 
 3511 
 3512 Release 2014b - 2014-03-24 21:28:50 -0700
 3513 
 3514   Changes affecting near-future timestamps
 3515 
 3516     Crimea switches to Moscow time on 2014-03-30 at 02:00 local time.
 3517     (Thanks to Alexander Krivenyshev.)  Move its zone.tab entry from UA to RU.
 3518 
 3519     New entry for Troll station, Antarctica.  (Thanks to Paul-Inge Flakstad and
 3520     Bengt-Inge Larsson.)  This is currently an approximation; a better version
 3521     will require the zic and localtime fixes mentioned below, and the plan is
 3522     to wait for a while until at least the zic fixes propagate.
 3523 
 3524   Changes affecting code
 3525 
 3526     'zic' and 'localtime' no longer reject locations needing four transitions
 3527     per year for the foreseeable future.  (Thanks to Andrew Main (Zefram).)
 3528     Also, 'zic' avoids some unlikely failures due to integer overflow.
 3529 
 3530   Changes affecting build procedure
 3531 
 3532     'make check' now detects Rule lines defined but never used.
 3533     The NZAQ rules, an instance of this problem, have been removed.
 3534 
 3535   Changes affecting commentary and documentation
 3536 
 3537     Fix Tuesday/Thursday typo in description of time in Israel.
 3538     (Thanks to Bert Katz via Pavel Kharitonov and Mike Frysinger.)
 3539 
 3540     Microsoft Windows 8.1 doesn't support tz database names.  (Thanks
 3541     to Donald MacQueen.)  Instead, the Microsoft Windows Store app
 3542     library supports them.
 3543 
 3544     Add comments about Johnston Island time in the 1960s.
 3545     (Thanks to Lyle McElhaney.)
 3546 
 3547     Morocco's 2014 DST start will be as predicted.
 3548     (Thanks to Sebastien Willemijns.)
 3549 
 3550 
 3551 Release 2014a - 2014-03-07 23:30:29 -0800
 3552 
 3553   Changes affecting near-future timestamps
 3554 
 3555     Turkey begins DST on 2014-03-31, not 03-30.  (Thanks to Faruk Pasin for
 3556     the heads-up, and to Tim Parenti for simplifying the update.)
 3557 
 3558   Changes affecting past timestamps
 3559 
 3560     Fiji ended DST on 2014-01-19 at 02:00, not the previously-scheduled 03:00.
 3561     (Thanks to Steffen Thorsen.)
 3562 
 3563     Ukraine switched from Moscow to Eastern European time on 1990-07-01
 3564     (not 1992-01-01), and observed DST during the entire next winter.
 3565     (Thanks to Vladimir in Moscow via Alois Treindl.)
 3566 
 3567     In 1988 Israel observed DST from 04-10 to 09-04, not 04-09 to 09-03.
 3568     (Thanks to Avigdor Finkelstein.)
 3569 
 3570   Changes affecting code
 3571 
 3572     A uninitialized-storage bug in 'localtime' has been fixed.
 3573     (Thanks to Logan Chien.)
 3574 
 3575   Changes affecting the build procedure
 3576 
 3577     The settings for 'make check_web' now default to Ubuntu 13.10.
 3578 
 3579   Changes affecting commentary and documentation
 3580 
 3581     The boundary of the US Pacific time zone is given more accurately.
 3582     (Thanks to Alan Mintz.)
 3583 
 3584     Chile's 2014 DST will be as predicted.  (Thanks to José Miguel Garrido.)
 3585 
 3586     Paraguay's 2014 DST will be as predicted.  (Thanks to Carlos Raúl Perasso.)
 3587 
 3588     Better descriptions of countries with same time zone history as
 3589     Trinidad and Tobago since 1970.  (Thanks to Alan Barrett for suggestion.)
 3590 
 3591     Several changes affect tz-link.htm, the main web page.
 3592 
 3593       Mention Time.is (thanks to Even Scharning) and WX-now (thanks to
 3594       David Braverman).
 3595 
 3596       Mention xCal (Internet RFC 6321) and jCal.
 3597 
 3598       Microsoft has some support for tz database names.
 3599 
 3600       CLDR data formats include both XML and JSON.
 3601 
 3602       Mention Maggiolo's map of solar vs standard time.
 3603       (Thanks to Arthur David Olson.)
 3604 
 3605       Mention TZ4Net.  (Thanks to Matt Johnson.)
 3606 
 3607       Mention the timezone-olson Haskell package.
 3608 
 3609       Mention zeitverschiebung.net.  (Thanks to Martin Jäger.)
 3610 
 3611       Remove moribund links to daylight-savings-time.info and to
 3612       Simple Timer + Clocks.
 3613 
 3614       Update two links.  (Thanks to Oscar van Vlijmen.)
 3615 
 3616       Fix some formatting glitches, e.g., remove random newlines from
 3617       abbr elements' title attributes.
 3618 
 3619 
 3620 Release 2013i - 2013-12-17 07:25:23 -0800
 3621 
 3622   Changes affecting near-future timestamps:
 3623 
 3624     Jordan switches back to standard time at 00:00 on December 20, 2013.
 3625     The 2006-2011 transition schedule is planned to resume in 2014.
 3626     (Thanks to Steffen Thorsen.)
 3627 
 3628   Changes affecting past timestamps:
 3629 
 3630     In 2004, Cuba began DST on March 28, not April 4.
 3631     (Thanks to Steffen Thorsen.)
 3632 
 3633   Changes affecting code
 3634 
 3635     The compile-time flag NOSOLAR has been removed, as nowadays the
 3636     benefit of slightly shrinking runtime table size is outweighed by the
 3637     cost of disallowing potential future updates that exceed old limits.
 3638 
 3639   Changes affecting documentation and commentary
 3640 
 3641     The files solar87, solar88, and solar89 are no longer distributed.
 3642     They were a negative experiment - that is, a demonstration that
 3643     tz data can represent solar time only with some difficulty and error.
 3644     Their presence in the distribution caused confusion, as Riyadh
 3645     civil time was generally not solar time in those years.
 3646 
 3647     tz-link.htm now mentions Noda Time.  (Thanks to Matt Johnson.)
 3648 
 3649 
 3650 Release 2013h - 2013-10-25 15:32:32 -0700
 3651 
 3652   Changes affecting current and future timestamps:
 3653 
 3654     Libya has switched its UT offset back to +02 without DST, instead
 3655     of +01 with DST.  (Thanks to Even Scharning.)
 3656 
 3657     Western Sahara (Africa/El_Aaiun) uses Morocco's DST rules.
 3658     (Thanks to Gwillim Law.)
 3659 
 3660   Changes affecting future timestamps:
 3661 
 3662     Acre and (we guess) western Amazonas will switch from UT -04 to -05
 3663     on 2013-11-10.  This affects America/Rio_Branco and America/Eirunepe.
 3664     (Thanks to Steffen Thorsen.)
 3665 
 3666     Add entries for DST transitions in Morocco in the year 2038.
 3667     This avoids some year-2038 glitches introduced in 2013g.
 3668     (Thanks to Yoshito Umaoka for reporting the problem.)
 3669 
 3670   Changes affecting API
 3671 
 3672     The 'tzselect' command no longer requires the 'select' command,
 3673     and should now work with /bin/sh on more platforms.  It also works
 3674     around a bug in BusyBox awk before version 1.21.0.  (Thanks to
 3675     Patrick 'P. J.' McDermott and Alan Barrett.)
 3676 
 3677   Changes affecting code
 3678 
 3679     Fix localtime overflow bugs with 32-bit unsigned time_t.
 3680 
 3681     zdump no longer assumes sscanf returns maximal values on overflow.
 3682 
 3683   Changes affecting the build procedure
 3684 
 3685     The builder can specify which programs to use, if any, instead of
 3686     'ar' and 'ranlib', and libtz.a is now built locally before being
 3687     installed.  (Thanks to Michael Forney.)
 3688 
 3689     A dependency typo in the 'zdump' rule has been fixed.
 3690     (Thanks to Andrew Paprocki.)
 3691 
 3692     The Makefile has been simplified by assuming that 'mkdir -p' and 'cp -f'
 3693     work as specified by POSIX.2-1992 or later; this is portable nowadays.
 3694 
 3695     'make clean' no longer removes 'leapseconds', since it's
 3696     host-independent and is part of the distribution.
 3697 
 3698     The unused makefile macros TZCSRCS, TZDSRCS, DATESRCS have been removed.
 3699 
 3700   Changes affecting documentation and commentary
 3701 
 3702     tz-link.htm now mentions TC TIMEZONE's draft time zone service protocol
 3703     (thanks to Mike Douglass) and TimezoneJS.Date (thanks to Jim Fehrle).
 3704 
 3705     Update URLs in tz-link page.  Add URLs for Microsoft Windows, since
 3706     8.1 introduces tz support.  Remove URLs for Tru64 and UnixWare (no
 3707     longer maintained) and for old advisories.  SOFA now does C.
 3708 
 3709 Release 2013g - 2013-09-30 21:08:26 -0700
 3710 
 3711   Changes affecting current and near-future timestamps
 3712 
 3713     Morocco now observes DST from the last Sunday in March to the last
 3714     Sunday in October, not April to September respectively.  (Thanks
 3715     to Steffen Thorsen.)
 3716 
 3717   Changes affecting 'zic'
 3718 
 3719     'zic' now runs on platforms that lack both hard links and symlinks.
 3720     (Thanks to Theo Veenker for reporting the problem, for MinGW.)
 3721     Also, fix some bugs on platforms that lack hard links but have symlinks.
 3722 
 3723     'zic -v' again warns that Asia/Tehran has no POSIX environment variable
 3724     to predict the far future, fixing a bug introduced in 2013e.
 3725 
 3726   Changes affecting the build procedure
 3727 
 3728     The 'leapseconds' file is again put into the tzdata tarball.
 3729     Also, 'leapseconds.awk', so tzdata is self-contained.  (Thanks to
 3730     Matt Burgess and Ian Abbott.)  The timestamps of these and other
 3731     dependent files in tarballs are adjusted more consistently.
 3732 
 3733   Changes affecting documentation and commentary
 3734 
 3735     The README file is now part of the data tarball as well as the code.
 3736     It now states that files are public domain unless otherwise specified.
 3737     (Thanks to Andrew Main (Zefram) for asking for clarifications.)
 3738     Its details about the 1989 release moved to a place of honor near
 3739     the end of NEWS.
 3740 
 3741 
 3742 Release 2013f - 2013-09-24 23:37:36 -0700
 3743 
 3744   Changes affecting near-future timestamps
 3745 
 3746     Tocantins will very likely not observe DST starting this spring.
 3747     (Thanks to Steffen Thorsen.)
 3748 
 3749     Jordan will likely stay at UT +03 indefinitely, and will not fall
 3750     back this fall.
 3751 
 3752     Palestine will fall back at 00:00, not 01:00.  (Thanks to Steffen Thorsen.)
 3753 
 3754   Changes affecting API
 3755 
 3756     The types of the global variables 'timezone' and 'altzone' (if present)
 3757     have been changed back to 'long'.  This is required for 'timezone'
 3758     by POSIX, and for 'altzone' by common practice, e.g., Solaris 11.
 3759     These variables were originally 'long' in the tz code, but were
 3760     mistakenly changed to 'time_t' in 1987; nobody reported the
 3761     incompatibility until now.  The difference matters on x32, where
 3762     'long' is 32 bits and 'time_t' is 64.  (Thanks to Elliott Hughes.)
 3763 
 3764   Changes affecting the build procedure
 3765 
 3766     Avoid long strings in leapseconds.awk to work around a mawk bug.
 3767     (Thanks to Cyril Baurand.)
 3768 
 3769   Changes affecting documentation and commentary
 3770 
 3771     New file 'NEWS' that contains release notes like this one.
 3772 
 3773     Paraguay's law does not specify DST transition time; 00:00 is customary.
 3774     (Thanks to Waldemar Villamayor-Venialbo.)
 3775 
 3776     Minor capitalization fixes.
 3777 
 3778   Changes affecting version-control only
 3779 
 3780     The experimental GitHub repository now contains annotated and
 3781     signed tags for recent releases, e.g., '2013e' for Release 2013e.
 3782     Releases are tagged starting with 2012e; earlier releases were
 3783     done differently, and tags would either not have a simple name or
 3784     not exactly match what was released.
 3785 
 3786     'make set-timestamps' is now simpler and a bit more portable.
 3787 
 3788 
 3789 Release 2013e - 2013-09-19 23:50:04 -0700
 3790 
 3791   Changes affecting near-future timestamps
 3792 
 3793     This year Fiji will start DST on October 27, not October 20.
 3794     (Thanks to David Wheeler for the heads-up.)  For now, guess that
 3795     Fiji will continue to spring forward the Sunday before the fourth
 3796     Monday in October.
 3797 
 3798   Changes affecting current and future time zone abbreviations
 3799 
 3800     Use WIB/WITA/WIT rather than WIT/CIT/EIT for alphabetic Indonesian
 3801     time zone abbreviations since 1932.  (Thanks to George Ziegler,
 3802     Priyadi Iman Nurcahyo, Zakaria, Jason Grimes, Martin Pitt, and
 3803     Benny Lin.)  This affects Asia/Dili, Asia/Jakarta, Asia/Jayapura,
 3804     Asia/Makassar, and Asia/Pontianak.
 3805 
 3806     Use ART (UT -03, standard time), rather than WARST (also -03, but
 3807     daylight saving time) for San Luis, Argentina since 2009.
 3808 
 3809   Changes affecting Godthåb timestamps after 2037 if version mismatch
 3810 
 3811     Allow POSIX-like TZ strings where the transition time's hour can
 3812     range from -167 through 167, instead of the POSIX-required 0
 3813     through 24.  E.g., TZ='FJT-12FJST,M10.3.1/146,M1.3.4/75' for the
 3814     new Fiji rules.  This is a more-compact way to represent
 3815     far-future timestamps for America/Godthab, America/Santiago,
 3816     Antarctica/Palmer, Asia/Gaza, Asia/Hebron, Asia/Jerusalem,
 3817     Pacific/Easter, and Pacific/Fiji.  Other zones are unaffected by
 3818     this change.  (Derived from a suggestion by Arthur David Olson.)
 3819 
 3820     Allow POSIX-like TZ strings where daylight saving time is in
 3821     effect all year.  E.g., TZ='WART4WARST,J1/0,J365/25' for Western
 3822     Argentina Summer Time all year.  This supports a more-compact way
 3823     to represent the 2013d data for America/Argentina/San_Luis.
 3824     Because of the change for San Luis noted above this change does not
 3825     affect the current data.  (Thanks to Andrew Main (Zefram) for
 3826     suggestions that improved this change.)
 3827 
 3828     Where these two TZ changes take effect, there is a minor extension
 3829     to the tz file format in that it allows new values for the
 3830     embedded TZ-format string, and the tz file format version number
 3831     has therefore been increased from 2 to 3 as a precaution.
 3832     Version-2-based client code should continue to work as before for
 3833     all timestamps before 2038.  Existing version-2-based client code
 3834     (tzcode, GNU/Linux, Solaris) has been tested on version-3-format
 3835     files, and typically works in practice even for timestamps after
 3836     2037; the only known exception is America/Godthab.
 3837 
 3838   Changes affecting timestamps before 1970
 3839 
 3840     Pacific/Johnston is now a link to Pacific/Honolulu.  This corrects
 3841     some errors before 1947.
 3842 
 3843     Some zones have been turned into links, when they differ from existing
 3844     zones only in older data entries that were likely invented or that
 3845     differ only in LMT or transitions from LMT.  These changes affect
 3846     only timestamps before 1943.  The affected zones are:
 3847     Africa/Juba, America/Anguilla, America/Aruba, America/Dominica,
 3848     America/Grenada, America/Guadeloupe, America/Marigot,
 3849     America/Montserrat, America/St_Barthelemy, America/St_Kitts,
 3850     America/St_Lucia, America/St_Thomas, America/St_Vincent,
 3851     America/Tortola, and Europe/Vaduz.  (Thanks to Alois Treindl for
 3852     confirming that the old Europe/Vaduz zone was wrong and the new
 3853     link is better for WWII-era times.)
 3854 
 3855     Change Kingston Mean Time from -5:07:12 to -5:07:11.  This affects
 3856     America/Cayman, America/Jamaica and America/Grand_Turk timestamps
 3857     from 1890 to 1912.
 3858 
 3859     Change the UT offset of Bern Mean Time from 0:29:44 to 0:29:46.
 3860     This affects Europe/Zurich timestamps from 1853 to 1894.  (Thanks
 3861     to Alois Treindl.)
 3862 
 3863     Change the date of the circa-1850 Zurich transition from 1849-09-12
 3864     to 1853-07-16, overriding Shanks with data from Messerli about
 3865     postal and telegraph time in Switzerland.
 3866 
 3867   Changes affecting time zone abbreviations before 1970
 3868 
 3869     For Asia/Jakarta, use BMT (not JMT) for mean time from 1923 to 1932,
 3870     as Jakarta was called Batavia back then.
 3871 
 3872   Changes affecting API
 3873 
 3874     The 'zic' command now outputs a dummy transition when far-future
 3875     data can't be summarized using a TZ string, and uses a 402-year
 3876     window rather than a 400-year window.  For the current data, this
 3877     affects only the Asia/Tehran file.  It does not affect any of the
 3878     timestamps that this file represents, so zdump outputs the same
 3879     information as before.  (Thanks to Andrew Main (Zefram).)
 3880 
 3881     The 'date' command has a new '-r' option, which lets you specify
 3882     the integer time to display, a la FreeBSD.
 3883 
 3884     The 'tzselect' command has two new options '-c' and '-n', which lets you
 3885     select a zone based on latitude and longitude.
 3886 
 3887     The 'zic' command's '-v' option now warns about constructs that
 3888     require the new version-3 binary file format.  (Thanks to Arthur
 3889     David Olson for the suggestion.)
 3890 
 3891     Support for floating-point time_t has been removed.
 3892     It was always dicey, and POSIX no longer requires it.
 3893     (Thanks to Eric Blake for suggesting to the POSIX committee to
 3894     remove it, and thanks to Alan Barrett, Clive D.W. Feather, Andy
 3895     Heninger, Arthur David Olson, and Alois Treindl, for reporting
 3896     bugs and elucidating some of the corners of the old floating-point
 3897     implementation.)
 3898 
 3899     The signatures of 'offtime', 'timeoff', and 'gtime' have been
 3900     changed back to the old practice of using 'long' to represent UT
 3901     offsets.  This had been inadvertently and mistakenly changed to
 3902     'int_fast32_t'.  (Thanks to Christos Zoulas.)
 3903 
 3904     The code avoids undefined behavior on integer overflow in some
 3905     more places, including gmtime, localtime, mktime and zdump.
 3906 
 3907   Changes affecting the zdump utility
 3908 
 3909     zdump now outputs "UT" when referring to Universal Time, not "UTC".
 3910     "UTC" does not make sense for timestamps that predate the introduction
 3911     of UTC, whereas "UT", a more-generic term, does.  (Thanks to Steve Allen
 3912     for clarifying UT vs UTC.)
 3913 
 3914   Data changes affecting behavior of tzselect and similar programs
 3915 
 3916     Country code BQ is now called the more-common name "Caribbean Netherlands"
 3917     rather than the more-official "Bonaire, St Eustatius & Saba".
 3918 
 3919     Remove from zone.tab the names America/Montreal, America/Shiprock,
 3920     and Antarctica/South_Pole, as they are equivalent to existing
 3921     same-country-code zones for post-1970 timestamps.  The data entries for
 3922     these names are unchanged, so the names continue to work as before.
 3923 
 3924   Changes affecting code internals
 3925 
 3926     zic -c now runs way faster on 64-bit hosts when given large numbers.
 3927 
 3928     zic now uses vfprintf to avoid allocating and freeing some memory.
 3929 
 3930     tzselect now computes the list of continents from the data,
 3931     rather than have it hard-coded.
 3932 
 3933     Minor changes pacify GCC 4.7.3 and GCC 4.8.1.
 3934 
 3935   Changes affecting the build procedure
 3936 
 3937     The 'leapseconds' file is now generated automatically from a
 3938     new file 'leap-seconds.list', which is a copy of
 3939     <ftp://ftp.nist.gov/pub/time/leap-seconds.list>
 3940     A new source file 'leapseconds.awk' implements this.
 3941     The goal is simplification of the future maintenance of 'leapseconds'.
 3942 
 3943     When building the 'posix' or 'right' subdirectories, if the
 3944     subdirectory would be a copy of the default subdirectory, it is
 3945     now made a symbolic link if that is supported.  This saves about
 3946     2 MB of file system space.
 3947 
 3948     The links America/Shiprock and Antarctica/South_Pole have been
 3949     moved to the 'backward' file.  This affects only nondefault builds
 3950     that omit 'backward'.
 3951 
 3952   Changes affecting version-control only
 3953 
 3954     .gitignore now ignores 'date'.
 3955 
 3956   Changes affecting documentation and commentary
 3957 
 3958     Changes to the 'tzfile' man page
 3959 
 3960       It now mentions that the binary file format may be extended in
 3961       future versions by appending data.
 3962 
 3963       It now refers to the 'zdump' and 'zic' man pages.
 3964 
 3965     Changes to the 'zic' man page
 3966 
 3967       It lists conditions that elicit a warning with '-v'.
 3968 
 3969       It says that the behavior is unspecified when duplicate names
 3970       are given, or if the source of one link is the target of another.
 3971 
 3972       Its examples are updated to match the latest data.
 3973 
 3974       The definition of white space has been clarified slightly.
 3975       (Thanks to Michael Deckers.)
 3976 
 3977     Changes to the 'Theory' file
 3978 
 3979       There is a new section about the accuracy of the tz database,
 3980       describing the many ways that errors can creep in, and
 3981       explaining why so many of the pre-1970 timestamps are wrong or
 3982       misleading (thanks to Steve Allen, Lester Caine, and Garrett
 3983       Wollman for discussions that contributed to this).
 3984 
 3985       The 'Theory' file describes LMT better (this follows a
 3986       suggestion by Guy Harris).
 3987 
 3988       It refers to the 2013 edition of POSIX rather than the 2004 edition.
 3989 
 3990       It's mentioned that excluding 'backward' should not affect the
 3991       other data, and it suggests at least one zone.tab name per
 3992       inhabited country (thanks to Stephen Colebourne).
 3993 
 3994       Some longstanding restrictions on names are documented, e.g.,
 3995       'America/New_York' precludes 'America/New_York/Bronx'.
 3996 
 3997       It gives more reasons for the 1970 cutoff.
 3998 
 3999       It now mentions which time_t variants are supported, such as
 4000       signed integer time_t.  (Thanks to Paul Goyette for reporting
 4001       typos in an experimental version of this change.)
 4002 
 4003       (Thanks to Philip Newton for correcting typos in these changes.)
 4004 
 4005     Documentation and commentary is more careful to distinguish UT in
 4006     general from UTC in particular.  (Thanks to Steve Allen.)
 4007 
 4008     Add a better source for the Zurich 1894 transition.
 4009     (Thanks to Pierre-Yves Berger.)
 4010 
 4011     Update shapefile citations in tz-link.htm.  (Thanks to Guy Harris.)
 4012 
 4013 
 4014 Release 2013d - 2013-07-05 07:38:01 -0700
 4015 
 4016   Changes affecting future timestamps:
 4017 
 4018     Morocco's midsummer transitions this year are July 7 and August 10,
 4019     not July 9 and August 8.  (Thanks to Andrew Paprocki.)
 4020 
 4021     Israel now falls back on the last Sunday of October.
 4022     (Thanks to Ephraim Silverberg.)
 4023 
 4024   Changes affecting past timestamps:
 4025 
 4026     Specify Jerusalem's location more precisely; this changes the pre-1880
 4027     times by 2 s.
 4028 
 4029   Changing affecting metadata only:
 4030 
 4031     Fix typos in the entries for country codes BQ and SX.
 4032 
 4033   Changes affecting code:
 4034 
 4035     Rework the code to fix a bug with handling Australia/Macquarie on
 4036     32-bit hosts (thanks to Arthur David Olson).
 4037 
 4038     Port to platforms like NetBSD, where time_t can be wider than long.
 4039 
 4040     Add support for testing time_t types other than the system's.
 4041     Run 'make check_time_t_alternatives' to try this out.
 4042     Currently, the tests fail for unsigned time_t;
 4043     this should get fixed at some point.
 4044 
 4045   Changes affecting documentation and commentary:
 4046 
 4047     Deemphasize the significance of national borders.
 4048 
 4049     Update the zdump man page.
 4050 
 4051     Remove obsolete NOID comment (thanks to Denis Excoffier).
 4052 
 4053     Update several URLs and comments in the web pages.
 4054 
 4055     Spelling fixes (thanks to Kevin Lyda and Jonathan Leffler).
 4056 
 4057     Update URL for CLDR Zone->Tzid table (thanks to Yoshito Umaoka).
 4058 
 4059 
 4060 Release 2013c - 2013-04-19 16:17:40 -0700
 4061 
 4062   Changes affecting current and future timestamps:
 4063 
 4064     Palestine observed DST starting March 29, 2013.  (Thanks to
 4065     Steffen Thorsen.)  From 2013 on, Gaza and Hebron both observe DST,
 4066     with the predicted rules being the last Thursday in March at 24:00
 4067     to the first Friday on or after September 21 at 01:00.
 4068 
 4069     Assume that the recent change to Paraguay's DST rules is permanent,
 4070     by moving the end of DST to the 4th Sunday in March every year.
 4071     (Thanks to Carlos Raúl Perasso.)
 4072 
 4073   Changes affecting past timestamps:
 4074 
 4075     Fix some historical data for Palestine to agree with that of
 4076     timeanddate.com, as follows:
 4077 
 4078 	  The spring 2008 change in Gaza and Hebron was on 00:00 Mar 28, not
 4079 	  00:00 Apr 1.
 4080 
 4081 	  The fall 2009 change in Gaza and Hebron on Sep 4 was at 01:00, not
 4082 	  02:00.
 4083 
 4084 	  The spring 2010 change in Hebron was 00:00 Mar 26, not 00:01 Mar 27.
 4085 
 4086 	  The spring 2011 change in Gaza was 00:01 Apr 1, not 12:01 Apr 2.
 4087 
 4088 	  The spring 2011 change in Hebron on Apr 1 was at 00:01, not 12:01.
 4089 
 4090 	  The fall 2011 change in Hebron on Sep 30 was at 00:00, not 03:00.
 4091 
 4092     Fix times of habitation for Macquarie to agree with the Tasmania
 4093     Parks & Wildlife Service history, which indicates that permanent
 4094     habitation was 1899-1919 and 1948 on.
 4095 
 4096   Changing affecting metadata only:
 4097 
 4098     Macquarie Island is politically part of Australia, not Antarctica.
 4099     (Thanks to Tobias Conradi.)
 4100 
 4101     Sort Macquarie more-consistently with other parts of Australia.
 4102     (Thanks to Tim Parenti.)
 4103 
 4104 
 4105 Release 2013b - 2013-03-10 22:33:40 -0700
 4106 
 4107   Changes affecting current and future timestamps:
 4108 
 4109     Haiti uses US daylight-saving rules this year, and presumably future years.
 4110     This changes timestamps starting today.  (Thanks to Steffen Thorsen.)
 4111 
 4112     Paraguay will end DST on March 24 this year.
 4113     (Thanks to Steffen Thorsen.)  For now, assume it's just this year.
 4114 
 4115     Morocco does not observe DST during Ramadan;
 4116     try to predict Ramadan in Morocco as best we can.
 4117     (Thanks to Erik Homoet for the heads-up.)
 4118 
 4119   Changes affecting commentary:
 4120 
 4121     Update URLs in tz-link page.  Add URLs for webOS, BB10, iOS.
 4122     Update URL for Solaris.  Mention Internet RFC 6557.
 4123     Update Internet RFCs 2445->5545, 2822->5322.
 4124     Switch from FTP to HTTP for Internet RFCs.
 4125 
 4126 
 4127 Release 2013a - 2013-02-27 09:20:35 -0800
 4128 
 4129   Change affecting binary data format:
 4130 
 4131     The zone offset at the end of version-2-format zone files is now
 4132     allowed to be 24:00, as per POSIX.1-2008.  (Thanks to Arthur David Olson.)
 4133 
 4134   Changes affecting current and future timestamps:
 4135 
 4136     Chile's 2013 rules, and we guess rules for 2014 and later, will be
 4137     the same as 2012, namely Apr Sun>=23 03:00 UTC to Sep Sun>=2 04:00 UTC.
 4138     (Thanks to Steffen Thorsen and Robert Elz.)
 4139 
 4140     New Zones Asia/Khandyga, Asia/Ust-Nera, Europe/Busingen.
 4141     (Thanks to Tobias Conradi and Arthur David Olson.)
 4142 
 4143   Many changes affect historical timestamps before 1940.
 4144   These were deduced from: Milne J. Civil time. Geogr J. 1899
 4145   Feb;13(2):173-94 <https://www.jstor.org/stable/1774359>.
 4146 
 4147   Changes affecting the code:
 4148 
 4149     Fix zic bug that mishandled Egypt's 2010 changes (this also affected
 4150     the data).  (Thanks to Arthur David Olson.)
 4151 
 4152     Fix localtime bug when time_t is unsigned and data files were generated
 4153     by a signed time_t system.  (Thanks to Doug Bailey for reporting and
 4154     to Arthur David Olson for fixing.)
 4155 
 4156     Allow the email address for bug reports to be set by the packager.
 4157     The default is tz@iana.org, as before.  (Thanks to Joseph S. Myers.)
 4158 
 4159     Update HTML checking to be compatible with Ubuntu 12.10.
 4160 
 4161     Check that files are a safe subset of ASCII.  At some point we may
 4162     relax this requirement to a safe subset of UTF-8.  Without the
 4163     check, some non-UTF-8 encodings were leaking into the distribution.
 4164 
 4165   Commentary changes:
 4166 
 4167     Restore a comment about copyright notices that was inadvertently deleted.
 4168     (Thanks to Arthur David Olson.)
 4169 
 4170     Improve the commentary about which districts observe what times
 4171     in Russia.  (Thanks to Oscar van Vlijmen and Arthur David Olson.)
 4172 
 4173     Add web page links to tz.js.
 4174 
 4175     Add "Run by the Monkeys" to tz-art.  (Thanks to Arthur David Olson.)
 4176 
 4177 
 4178 Release 2012j - 2012-11-12 18:34:49 -0800
 4179 
 4180   Libya moved to CET this weekend, but with DST planned next year.
 4181   (Thanks to Even Scharning, Steffen Thorsen, and Tim Parenti.)
 4182 
 4183   Signatures now have the extension .asc, not .sign, as that's more
 4184   standard.  (Thanks to Phil Pennock.)
 4185 
 4186   The output of 'zdump --version', and of 'zic --version', now
 4187   uses a format that is more typical for --version.
 4188   (Thanks to Joseph S. Myers.)
 4189 
 4190   The output of 'tzselect --help', 'zdump --help', and 'zic --help'
 4191   now uses tz@iana.org rather than the old elsie address.
 4192 
 4193   zic -v now complains about abbreviations that are less than 3
 4194   or more than 6 characters, as per Posix.  Formerly, it checked
 4195   for abbreviations that were more than 3.
 4196 
 4197   'make public' no longer puts its temporary directory under /tmp,
 4198   and uses the just-built zic rather than the system zic.
 4199 
 4200   Various fixes to documentation and commentary.
 4201 
 4202 
 4203 Release 2012i - 2012-11-03 12:57:09 -0700
 4204 
 4205   Cuba switches from DST tomorrow at 01:00.  (Thanks to Steffen Thorsen.)
 4206 
 4207   Linker flags can now be specified via LDFLAGS.
 4208   AWK now defaults to 'awk', not 'nawk'.
 4209   The shell in tzselect now defaults to /bin/bash, but this can
 4210   be overridden by specifying KSHELL.
 4211   The main web page now mentions the unofficial GitHub repository.
 4212   (Thanks to Mike Frysinger.)
 4213 
 4214   Tarball signatures can now be built by running 'make signatures'.
 4215   There are also new makefile rules 'tarballs', 'check_public', and
 4216   separate makefile rules for each tarball and signature file.
 4217   A few makefile rules are now more portable to strict POSIX.
 4218 
 4219   The main web page now lists the canonical IANA URL.
 4220 
 4221 
 4222 Release 2012h - 2012-10-26 22:49:10 -0700
 4223 
 4224   Bahia no longer has DST.  (Thanks to Kelley Cook.)
 4225 
 4226   Tocantins has DST.  (Thanks to Rodrigo Severo.)
 4227 
 4228   Israel has new DST rules next year.  (Thanks to Ephraim Silverberg.)
 4229 
 4230   Jordan stays on DST this winter.  (Thanks to Steffen Thorsen.)
 4231 
 4232   Web page updates.
 4233 
 4234   More C modernization, except that at Arthur David Olson's suggestion
 4235   the instances of 'register' were kept.
 4236 
 4237 
 4238 Release 2012g - 2012-10-17 20:59:45 -0700
 4239 
 4240   Samoa fall 2012 and later.  (Thanks to Nicholas Pereira and Robert Elz.)
 4241 
 4242   Palestine fall 2012.  (Thanks to Steffen Thorsen.)
 4243 
 4244   Assume C89.
 4245 
 4246   To attack the version-number problem, this release ships the file
 4247   'Makefile' (which contains the release number) in both the tzcode and
 4248   the tzdata tarballs.  The two Makefiles are identical, and should be
 4249   identical in any matching pair of tarballs, so it shouldn't matter
 4250   which order you extract the tarballs.  Perhaps we can come up with a
 4251   better version-number scheme at some point; this scheme does have the
 4252   virtue of not adding more files.
 4253 
 4254 
 4255 Release 2012f - 2012-09-12 23:17:03 -0700
 4256 
 4257   * australasia (Pacific/Fiji): Fiji DST is October 21 through January
 4258     20 this year.  (Thanks to Steffen Thorsen.)
 4259 
 4260 
 4261 Release 2012e - 2012-08-02 20:44:55 -0700
 4262 
 4263   * australasia (Pacific/Fakaofo): Tokelau is UT +13, not +14.
 4264     (Thanks to Steffen Thorsen.)
 4265 
 4266   * Use a single version number for both code and data.
 4267 
 4268   * .gitignore: New file.
 4269 
 4270   * Remove trailing white space.
 4271 
 4272 
 4273 Release code2012c-data2012d - 2012-07-19 16:35:33 -0700
 4274 
 4275   Changes for Morocco's timestamps, which take effect in a couple of
 4276   hours, along with infrastructure changes to accommodate how the tz
 4277   code and data are released on IANA.
 4278 
 4279 
 4280 Release data2012c - 2012-03-27 12:17:25 -0400
 4281 
 4282   africa
 4283 	Summer time changes for Morocco (to start late April 2012)
 4284 
 4285   asia
 4286 	Changes for 2012 for Gaza & the West Bank (Hebron) and Syria
 4287 
 4288   northamerica
 4289 	Haiti following US/Canada rules for 2012 (and we're assuming,
 4290 	for now anyway, for the future).
 4291 
 4292 
 4293 Release 2012b - 2012-03-02 12:29:15 +0700
 4294 
 4295   There is just one change to tzcode2012b (compared with 2012a):
 4296   the Makefile that was accidentally included with 2012a has been
 4297   replaced with the version that should have been there, which is
 4298   identical with the previous version (from tzcode2011i).
 4299 
 4300   There are just two changes in tzdata2012b compared with 2012a.
 4301 
 4302   Most significantly, summer time in Cuba has been delayed 3 weeks
 4303   (now starts April 1 rather than March 11).   Since Mar 11 (the old start
 4304   date, as listed in 2012a) is just a little over a week away, this
 4305   change is urgent.
 4306 
 4307   Less importantly, an excess tab in one of the changes in zone.tab
 4308   in 2012a has been removed.
 4309 
 4310 
 4311 Release 2012a - 2012-03-01 18:28:10 +0700
 4312 
 4313   The changes in tzcode2012a (compared to the previous version, 2011i)
 4314   are entirely to the README and tz-art.htm and tz-link.htm files, if
 4315   none of those concern you, you can ignore the code update.  The changes
 4316   reflect the changed addresses for the mailing list and the code and
 4317   data distribution points & methods (and a link to DateTime::TimeZone::Tzfile
 4318   has been added to tz-link.htm).
 4319 
 4320   In tzdata2012a (compared to the previous release, which was 2011n)
 4321   the major changes are:
 4322 	Chile 2011/2012 and 2012/2013 summer time date adjustments.
 4323 	Falkland Islands onto permanent summer time (we're assuming for the
 4324 		foreseeable future, though 2012 is all we're fairly certain of.)
 4325 	Armenia has abolished Summer Time.
 4326 	Tokelau jumped the International Date Line back last December
 4327 		(just the same as their near neighbour, Samoa).
 4328 	America/Creston is a new zone for a small area of British Columbia
 4329 	There will be a leapsecond 2012-06-30 23:59:60 UTC.
 4330 
 4331   Other minor changes are:
 4332 	Corrections to 1918 Canadian summer time end dates.
 4333 	Updated URL for UK time zone history (in comments)
 4334 	A few typos in Le Corre's list of free French place names (comments)
 4335 
 4336 
 4337 Release data2011n - 2011-10-30 14:57:54 +0700
 4338 
 4339   There are three changes of note - most urgently, Cuba (America/Havana)
 4340   has extended summer time by two weeks, now to end on Nov 13, rather than
 4341   the (already past) Oct 30.   Second, the Pridnestrovian Moldavian Republic
 4342   (Europe/Tiraspol) decided not to split from the rest of Moldova after
 4343   all, and consequently that zone has been removed (again) and reinstated
 4344   in the "backward" file as a link to Europe/Chisinau.   And third, the
 4345   end date for Fiji's summer time this summer was moved forward from the
 4346   earlier planned Feb 26, to Jan 22.
 4347 
 4348   Apart from that, Moldova (MD) returns to a single entry in zone.tab
 4349   (and the incorrect syntax that was in the 2011m version of that file
 4350   is so fixed - it would have been fixed in a different way had this
 4351   change not happened - that's the "missing" sccs version id).
 4352 
 4353 
 4354 Release data2011m - 2011-10-24 21:42:16 +0700
 4355 
 4356   In particular, the typos in comments in the data (2011-11-17 should have
 4357   been 2011-10-17 as Alan Barrett noted, and spelling of Tiraspol that
 4358   Tim Parenti noted) have been fixed, and the change for Ukraine has been
 4359   made in all 4 Ukrainian zones, rather than just Kiev (again, thanks to
 4360   Tim Parenti, and also Denys Gavrysh)
 4361 
 4362   In addition, I added Europe/Tiraspol to zone.tab.
 4363 
 4364   This time, all the files have new version numbers...  (including the files
 4365   otherwise unchanged in 2011m that were changed in 2011l but didn't get new
 4366   version numbers there...)
 4367 
 4368 
 4369 Release data2011l - 2011-10-10 11:15:43 +0700
 4370 
 4371   There are just 2 changes that cause different generated tzdata files from
 4372   zic, to Asia/Hebron and Pacific/Fiji - the possible change for Bahia, Brazil
 4373   is included, but commented out.  Compared with the diff I sent out last week,
 4374   this version also includes attributions for the sources for the changes
 4375   (in much the same format as ado used, but the html tags have not been
 4376   checked, verified, or used in any way at all, so if there are errors there,
 4377   please let me know.)
 4378 
 4379 
 4380 Release data2011k - 2011-09-20 17:54:03 -0400
 4381 
 4382   [not summarized]
 4383 
 4384 
 4385 Release data2011j - 2011-09-12 09:22:49 -0400
 4386 
 4387   (contemporary changes for Samoa; past changes for Kenya, Uganda, and
 4388   Tanzania); there are also two spelling corrections to comments in
 4389   the australasia file (with thanks to Christos Zoulas).
 4390 
 4391 
 4392 Release 2011i - 2011-08-29 05:56:32 -0400
 4393 
 4394   [not summarized]
 4395 
 4396 
 4397 Release data2011h - 2011-06-15 18:41:48 -0400
 4398 
 4399   Russia and Curaçao changes
 4400 
 4401 
 4402 Release 2011g - 2011-04-25 09:07:22 -0400
 4403 
 4404   update the rules for Egypt to reflect its abandonment of DST this year
 4405 
 4406 
 4407 Release 2011f - 2011-04-06 17:14:53 -0400
 4408 
 4409   [not summarized]
 4410 
 4411 
 4412 Release 2011e - 2011-03-31 16:04:38 -0400
 4413 
 4414   Morocco, Chile, and tz-link changes
 4415 
 4416 
 4417 Release 2011d - 2011-03-14 09:18:01 -0400
 4418 
 4419   changes that impact present-day timestamps in Cuba, Samoa, and Turkey
 4420 
 4421 
 4422 Release 2011c - 2011-03-07 09:30:09 -0500
 4423 
 4424   These do affect current timestamps in Chile and Annette Island, Canada.
 4425 
 4426 
 4427 Release 2011b - 2011-02-07 08:44:50 -0500
 4428 
 4429   [not summarized]
 4430 
 4431 
 4432 Release 2011a - 2011-01-24 10:30:16 -0500
 4433 
 4434   [not summarized]
 4435 
 4436 
 4437 Release data2010o - 2010-11-01 09:18:23 -0400
 4438 
 4439   change to the end of DST in Fiji in 2011
 4440 
 4441 
 4442 Release 2010n - 2010-10-25 08:19:17 -0400
 4443 
 4444   [not summarized]
 4445 
 4446 
 4447 Release 2010m - 2010-09-27 09:24:48 -0400
 4448 
 4449   Hong Kong, Vostok, and zic.c changes
 4450 
 4451 
 4452 Release 2010l - 2010-08-16 06:57:25 -0400
 4453 
 4454   [not summarized]
 4455 
 4456 
 4457 Release 2010k - 2010-07-26 10:42:27 -0400
 4458 
 4459   [not summarized]
 4460 
 4461 
 4462 Release 2010j - 2010-05-10 09:07:48 -0400
 4463 
 4464   changes for Bahía de Banderas and for version naming
 4465 
 4466 
 4467 Release data2010i - 2010-04-16 18:50:45 -0400
 4468 
 4469   the end of DST in Morocco on 2010-08-08
 4470 
 4471 
 4472 Release data2010h - 2010-04-05 09:58:56 -0400
 4473 
 4474   [not summarized]
 4475 
 4476 
 4477 Release data2010g - 2010-03-24 11:14:53 -0400
 4478 
 4479   [not summarized]
 4480 
 4481 
 4482 Release 2010f - 2010-03-22 09:45:46 -0400
 4483 
 4484   [not summarized]
 4485 
 4486 
 4487 Release data2010e - 2010-03-08 14:24:27 -0500
 4488 
 4489   corrects the Dhaka bug found by Danvin Ruangchan
 4490 
 4491 
 4492 Release data2010d - 2010-03-06 07:26:01 -0500
 4493 
 4494   [not summarized]
 4495 
 4496 
 4497 Release 2010c - 2010-03-01 09:20:58 -0500
 4498 
 4499   changes including KRE's suggestion for earlier initialization of
 4500   "goahead" and "goback" structure elements
 4501 
 4502 
 4503 Release code2010a - 2010-02-16 10:40:04 -0500
 4504 
 4505   [not summarized]
 4506 
 4507 
 4508 Release data2010b - 2010-01-20 12:37:01 -0500
 4509 
 4510   Mexico changes
 4511 
 4512 
 4513 Release data2010a - 2010-01-18 08:30:04 -0500
 4514 
 4515   changes to Dhaka
 4516 
 4517 
 4518 Release data2009u - 2009-12-26 08:32:28 -0500
 4519 
 4520   changes to DST in Bangladesh
 4521 
 4522 
 4523 Release 2009t - 2009-12-21 13:24:27 -0500
 4524 
 4525   [not summarized]
 4526 
 4527 
 4528 Release data2009s - 2009-11-14 10:26:32 -0500
 4529 
 4530   (cosmetic) Antarctica change and the DST-in-Fiji-in-2009-and-2010 change
 4531 
 4532 
 4533 Release 2009r - 2009-11-09 10:10:31 -0500
 4534 
 4535   "antarctica" and "tz-link.htm" changes
 4536 
 4537 
 4538 Release 2009q - 2009-11-02 09:12:40 -0500
 4539 
 4540   with two corrections as reported by Eric Muller and Philip Newton
 4541 
 4542 
 4543 Release data2009p - 2009-10-23 15:05:27 -0400
 4544 
 4545   Argentina (including San Luis) changes (with the correction from
 4546   Mariano Absatz)
 4547 
 4548 
 4549 Release data2009o - 2009-10-14 16:49:38 -0400
 4550 
 4551   Samoa (commentary only), Pakistan, and Bangladesh changes
 4552 
 4553 
 4554 Release data2009n - 2009-09-22 15:13:38 -0400
 4555 
 4556   added commentary for Argentina and a change to the end of DST in
 4557   2009 in Pakistan
 4558 
 4559 
 4560 Release data2009m - 2009-09-03 10:23:43 -0400
 4561 
 4562   Samoa and Palestine changes
 4563 
 4564 
 4565 Release data2009l - 2009-08-14 09:13:07 -0400
 4566 
 4567   Samoa (comments only) and Egypt
 4568 
 4569 
 4570 Release 2009k - 2009-07-20 09:46:08 -0400
 4571 
 4572   [not summarized]
 4573 
 4574 
 4575 Release data2009j - 2009-06-15 06:43:59 -0400
 4576 
 4577   Bangladesh change (with a short turnaround since the DST change is
 4578   impending)
 4579 
 4580 
 4581 Release 2009i - 2009-06-08 09:21:22 -0400
 4582 
 4583   updating for DST in Bangladesh this year
 4584 
 4585 
 4586 Release 2009h - 2009-05-26 09:19:14 -0400
 4587 
 4588   [not summarized]
 4589 
 4590 
 4591 Release data2009g - 2009-04-20 16:34:07 -0400
 4592 
 4593   Cairo
 4594 
 4595 
 4596 Release data2009f - 2009-04-10 11:00:52 -0400
 4597 
 4598   correct DST in Pakistan
 4599 
 4600 
 4601 Release 2009e - 2009-04-06 09:08:11 -0400
 4602 
 4603   [not summarized]
 4604 
 4605 
 4606 Release 2009d - 2009-03-23 09:38:12 -0400
 4607 
 4608   Morocco, Tunisia, Argentina, and American Astronomical Society changes
 4609 
 4610 
 4611 Release data2009c - 2009-03-16 09:47:51 -0400
 4612 
 4613   change to the start of Cuban DST
 4614 
 4615 
 4616 Release 2009b - 2009-02-09 11:15:22 -0500
 4617 
 4618   [not summarized]
 4619 
 4620 
 4621 Release 2009a - 2009-01-21 10:09:39 -0500
 4622 
 4623   [not summarized]
 4624 
 4625 
 4626 Release data2008i - 2008-10-21 12:10:25 -0400
 4627 
 4628   southamerica and zone.tab files, with Argentina DST rule changes and
 4629   United States zone reordering and recommenting
 4630 
 4631 
 4632 Release 2008h - 2008-10-13 07:33:56 -0400
 4633 
 4634   [not summarized]
 4635 
 4636 
 4637 Release 2008g - 2008-10-06 09:03:18 -0400
 4638 
 4639   Fix a broken HTML anchor and update Brazil's DST transitions;
 4640   there's also a slight reordering of information in tz-art.htm.
 4641 
 4642 
 4643 Release data2008f - 2008-09-09 22:33:26 -0400
 4644 
 4645   [not summarized]
 4646 
 4647 
 4648 Release 2008e - 2008-07-28 14:11:17 -0400
 4649 
 4650   changes by Arthur David Olson and Jesper Nørgaard Welen
 4651 
 4652 
 4653 Release data2008d - 2008-07-07 09:51:38 -0400
 4654 
 4655   changes by Arthur David Olson, Paul Eggert, and Rodrigo Severo
 4656 
 4657 
 4658 Release data2008c - 2008-05-19 17:48:03 -0400
 4659 
 4660   Pakistan, Morocco, and Mongolia
 4661 
 4662 
 4663 Release data2008b - 2008-03-24 08:30:59 -0400
 4664 
 4665   including renaming Asia/Calcutta to Asia/Kolkata, with a backward
 4666   link provided
 4667 
 4668 
 4669 Release 2008a - 2008-03-08 05:42:16 -0500
 4670 
 4671   [not summarized]
 4672 
 4673 
 4674 Release 2007k - 2007-12-31 10:25:22 -0500
 4675 
 4676   most importantly, changes to the "southamerica" file based on
 4677   Argentina's readoption of daylight saving time
 4678 
 4679 
 4680 Release 2007j - 2007-12-03 09:51:01 -0500
 4681 
 4682   1. eliminate the "P" (parameter) macro;
 4683 
 4684   2. the "noncontroversial" changes circulated on the time zone
 4685   mailing list (less the changes to "logwtmp.c");
 4686 
 4687   3. eliminate "too many transition" errors when "min" is used in time
 4688   zone rules;
 4689 
 4690   4. changes by Paul Eggert (including updated information for Venezuela).
 4691 
 4692 
 4693 Release data2007i - 2007-10-30 10:28:11 -0400
 4694 
 4695   changes for Cuba and Syria
 4696 
 4697 
 4698 Release 2007h - 2007-10-01 10:05:51 -0400
 4699 
 4700   changes by Paul Eggert, as well as an updated link to the ICU
 4701   project in tz-link.htm
 4702 
 4703 
 4704 Release 2007g - 2007-08-20 10:47:59 -0400
 4705 
 4706   changes by Paul Eggert
 4707 
 4708   The "leapseconds" file has been updated to incorporate the most
 4709   recent International Earth Rotation and Reference Systems Service
 4710   (IERS) bulletin.
 4711 
 4712   There's an addition to tz-art.htm regarding the television show "Medium".
 4713 
 4714 
 4715 Release 2007f - 2007-05-07 10:46:46 -0400
 4716 
 4717   changes by Paul Eggert (including Haiti, Turks and Caicos, and New
 4718   Zealand)
 4719 
 4720   changes to zic.c to allow hour values greater than 24 (along with
 4721   Paul's improved time value overflow checking)
 4722 
 4723 
 4724 Release 2007e - 2007-04-02 10:11:52 -0400
 4725 
 4726   Syria and Honduras changes by Paul Eggert
 4727 
 4728   zic.c variable renaming changes by Arthur David Olson
 4729 
 4730 
 4731 Release 2007d - 2007-03-20 08:48:30 -0400
 4732 
 4733   changes by Paul Eggert
 4734 
 4735   the elimination of white space at the ends of lines
 4736 
 4737 
 4738 Release 2007c - 2007-02-26 09:09:37 -0500
 4739 
 4740   changes by Paul Eggert
 4741 
 4742 
 4743 Release 2007b - 2007-02-12 09:34:20 -0500
 4744 
 4745   Paul Eggert's proposed change to the quotation handling logic in zic.c.
 4746 
 4747   changes to the commentary in "leapseconds" reflecting the IERS
 4748   announcement that there is to be no positive leap second at the end
 4749   of June 2007.
 4750 
 4751 
 4752 Release 2007a - 2007-01-08 12:28:29 -0500
 4753 
 4754   changes by Paul Eggert
 4755 
 4756   Derick Rethans's Asmara change
 4757 
 4758   Oscar van Vlijmen's Easter Island local mean time change
 4759 
 4760   symbolic link changes
 4761 
 4762 
 4763 Release 2006p - 2006-11-27 08:54:27 -0500
 4764 
 4765   changes by Paul Eggert
 4766 
 4767 
 4768 Release 2006o - 2006-11-06 09:18:07 -0500
 4769 
 4770   changes by Paul Eggert
 4771 
 4772 
 4773 Release 2006n - 2006-10-10 11:32:06 -0400
 4774 
 4775   changes by Paul Eggert
 4776 
 4777 
 4778 Release 2006m - 2006-10-02 15:32:35 -0400
 4779 
 4780   changes for Uruguay, Palestine, and Egypt by Paul Eggert
 4781 
 4782   (minimalist) changes to zic.8 to clarify "until" information
 4783 
 4784 
 4785 Release data2006l - 2006-09-18 12:58:11 -0400
 4786 
 4787   Paul's best-effort work on this coming weekend's Egypt time change
 4788 
 4789 
 4790 Release 2006k - 2006-08-28 12:19:09 -0400
 4791 
 4792   changes by Paul Eggert
 4793 
 4794 
 4795 Release 2006j - 2006-08-21 09:56:32 -0400
 4796 
 4797   changes by Paul Eggert
 4798 
 4799 
 4800 Release code2006i - 2006-08-07 12:30:55 -0400
 4801 
 4802   localtime.c fixes
 4803 
 4804   Ken Pizzini's conversion script
 4805 
 4806 
 4807 Release code2006h - 2006-07-24 09:19:37 -0400
 4808 
 4809   adds public domain notices to four files
 4810 
 4811   includes a fix for transition times being off by a second
 4812 
 4813   adds a new recording to the "arts" file (information courtesy Colin Bowern)
 4814 
 4815 
 4816 Release 2006g - 2006-05-08 17:18:09 -0400
 4817 
 4818   northamerica changes by Paul Eggert
 4819 
 4820 
 4821 Release 2006f - 2006-05-01 11:46:00 -0400
 4822 
 4823   a missing version number problem is fixed (with thanks to Bradley
 4824   White for catching the problem)
 4825 
 4826 
 4827 Release 2006d - 2006-04-17 14:33:43 -0400
 4828 
 4829   changes by Paul Eggert
 4830 
 4831   added new items to tz-arts.htm that were found by Paul
 4832 
 4833 
 4834 Release 2006c - 2006-04-03 10:09:32 -0400
 4835 
 4836   two sets of data changes by Paul Eggert
 4837 
 4838   a fencepost error fix in zic.c
 4839 
 4840   changes to zic.c and the "europe" file to minimize differences
 4841   between output produced by the old 32-bit zic and the new 64-bit
 4842   version
 4843 
 4844 
 4845 Release 2006b - 2006-02-20 10:08:18 -0500
 4846   [tz32code2006b + tz64code2006b + tzdata2006b]
 4847 
 4848   64-bit code
 4849 
 4850   All SCCS IDs were bumped to "8.1" for this release.
 4851 
 4852 
 4853 Release 2006a - 2006-01-30 08:59:31 -0500
 4854 
 4855   changes by Paul Eggert (in particular, Indiana time zone moves)
 4856 
 4857   an addition to the zic manual page to describe how special-case
 4858   transitions are handled
 4859 
 4860 
 4861 Release 2005r - 2005-12-27 09:27:13 -0500
 4862 
 4863   Canadian changes by Paul Eggert
 4864 
 4865   They also add "<pre>" directives to time zone data files and reflect
 4866   changes to warning message logic in "zdump.c" (but with calls to
 4867   "gettext" kept unbundled at the suggestion of Ken Pizzini).
 4868 
 4869 
 4870 Release 2005q - 2005-12-13 09:17:09 -0500
 4871 
 4872   Nothing earth-shaking here:
 4873 	1.  Electronic mail addresses have been removed.
 4874 	2.  Casts of the return value of exit have been removed.
 4875 	3.  Casts of the argument of is.* macros have been added.
 4876 	4.  Indentation in one section of zic.c has been fixed.
 4877 	5.  References to dead URLs in the data files have been dealt with.
 4878 
 4879 
 4880 Release 2005p - 2005-12-05 10:30:53 -0500
 4881 
 4882   "systemv", "tz-link.htm", and "zdump.c" changes
 4883   (less the casts of arguments to the is* macros)
 4884 
 4885 
 4886 Release 2005o - 2005-11-28 10:55:26 -0500
 4887 
 4888   Georgia, Cuba, Nicaragua, and Jordan changes by Paul Eggert
 4889 
 4890   zdump.c lint fixes by Arthur David Olson
 4891 
 4892 
 4893 Release 2005n - 2005-10-03 09:44:09 -0400
 4894 
 4895   changes by Paul Eggert (both the Uruguay changes and the Kyrgyzstan
 4896   et al. changes)
 4897 
 4898 
 4899 Release 2005m - 2005-08-29 12:15:40 -0400
 4900 
 4901   changes by Paul Eggert (with a small tweak to the tz-art change)
 4902 
 4903   a declaration of an unused variable has been removed from zdump.c
 4904 
 4905 
 4906 Release 2005l - 2005-08-22 12:06:39 -0400
 4907 
 4908   changes by Paul Eggert
 4909 
 4910   overflow/underflow checks by Arthur David Olson, minus changes to
 4911   the "Theory" file about the pending addition of 64-bit data (I grow
 4912   less confident of the changes being accepted with each passing day,
 4913   and the changes no longer increase the data files nine-fold--there's
 4914   less than a doubling in size by my local Sun's reckoning)
 4915 
 4916 
 4917 Release 2005k - 2005-07-14 14:14:24 -0400
 4918 
 4919   The "leapseconds" file has been edited to reflect the recently
 4920   announced leap second at the end of 2005.
 4921 
 4922   I've also deleted electronic mail addresses from the files as an
 4923   anti-spam measure.
 4924 
 4925 
 4926 Release 2005j - 2005-06-13 14:34:13 -0400
 4927 
 4928   These reflect changes to limit the length of time zone abbreviations
 4929   and the characters used in those abbreviations.
 4930 
 4931   There are also changes to handle POSIX-style "quoted" timezone
 4932   environment variables.
 4933 
 4934   The changes were circulated on the time zone mailing list; the only
 4935   change since then was the removal of a couple of minimum-length of
 4936   abbreviation checks.
 4937 
 4938 
 4939 Release data2005i - 2005-04-21 15:04:16 -0400
 4940 
 4941   changes (most importantly to Nicaragua and Haiti) by Paul Eggert
 4942 
 4943 
 4944 Release 2005h - 2005-04-04 11:24:47 -0400
 4945 
 4946   changes by Paul Eggert
 4947 
 4948   minor changes to Makefile and zdump.c to produce more useful output
 4949   when doing a "make typecheck"
 4950 
 4951 
 4952 Release 2005g - 2005-03-14 10:11:21 -0500
 4953 
 4954   changes by Paul Eggert (a change to current DST rules in Uruguay and
 4955   an update to a link to time zone software)
 4956 
 4957 
 4958 Release 2005f - 2005-03-01 08:45:32 -0500
 4959 
 4960   data and documentation changes by Paul Eggert
 4961 
 4962 
 4963 Release 2005e - 2005-02-10 15:59:44 -0500
 4964 
 4965   [not summarized]
 4966 
 4967 
 4968 Release code2005d - 2005-01-31 09:21:47 -0500
 4969 
 4970   make zic complain about links to links if the -v flag is used
 4971 
 4972   have "make public" do more code checking
 4973 
 4974   add an include to "localtime.c" for the benefit of gcc systems
 4975 
 4976 
 4977 Release 2005c - 2005-01-17 18:36:29 -0500
 4978 
 4979   get better results when mktime runs on a system where time_t is double
 4980 
 4981   changes to the data files (most importantly to Paraguay)
 4982 
 4983 
 4984 Release 2005b - 2005-01-10 09:19:54 -0500
 4985 
 4986   Get localtime and gmtime working on systems with exotic time_t types.
 4987 
 4988   Update the leap second commentary in the "leapseconds" file.
 4989 
 4990 
 4991 Release 2005a - 2005-01-01 13:13:44 -0500
 4992 
 4993   [not summarized]
 4994 
 4995 
 4996 Release code2004i - 2004-12-14 13:42:58 -0500
 4997 
 4998   Deal with systems where time_t is unsigned.
 4999 
 5000 
 5001 Release code2004h - 2004-12-07 11:40:18 -0500
 5002 
 5003   64-bit-time_t changes
 5004 
 5005 
 5006 Release 2004g - 2004-11-02 09:06:01 -0500
 5007 
 5008   update to Cuba (taking effect this weekend)
 5009 
 5010   other changes by Paul Eggert
 5011 
 5012   correction of the spelling of Oslo
 5013 
 5014   changed versions of difftime.c and private.h
 5015 
 5016 
 5017 Release code2004f - 2004-10-21 10:25:22 -0400
 5018 
 5019   Cope with wide-ranging tm_year values.
 5020 
 5021 
 5022 Release 2004e - 2004-10-11 14:47:21 -0400
 5023 
 5024   Brazil/Argentina/Israel changes by Paul Eggert
 5025 
 5026   changes to tz-link.htm by Paul
 5027 
 5028   one small fix to Makefile
 5029 
 5030 
 5031 Release 2004d - 2004-09-22 08:27:29 -0400
 5032 
 5033   Avoid overflow problems when TM_YEAR_BASE is added to an integer.
 5034 
 5035 
 5036 Release 2004c - 2004-08-11 12:06:26 -0400
 5037 
 5038   asctime-related changes
 5039 
 5040   (variants of) some of the documentation changes suggested by Paul Eggert
 5041 
 5042 
 5043 Release 2004b - 2004-07-19 14:33:35 -0400
 5044 
 5045   data changes by Paul Eggert - most importantly, updates for Argentina
 5046 
 5047 
 5048 Release 2004a - 2004-05-27 12:00:47 -0400
 5049 
 5050   changes by Paul Eggert
 5051 
 5052   Handle DST transitions that occur at the end of a month in some
 5053   years but at the start of the following month in other years.
 5054 
 5055   Add a copy of the correspondence that's the basis for claims about
 5056   DST in the Navajo Nation.
 5057 
 5058 
 5059 Release 2003e - 2003-12-15 09:36:47 -0500
 5060 
 5061   changes by Arthur David Olson (primarily code changes)
 5062 
 5063   changes by Paul Eggert (primarily data changes)
 5064 
 5065   minor changes to "Makefile" and "northamerica" (in the latter case,
 5066   optimization of the "Toronto" rules)
 5067 
 5068 
 5069 Release 2003d - 2003-10-06 09:34:44 -0400
 5070 
 5071   changes by Paul Eggert
 5072 
 5073 
 5074 Release 2003c - 2003-09-16 10:47:05 -0400
 5075 
 5076   Fix bad returns in zic.c's inleap function.
 5077   Thanks to Bradley White for catching the problem!
 5078 
 5079 
 5080 Release 2003b - 2003-09-16 07:13:44 -0400
 5081 
 5082   Add a "--version" option (and documentation) to the zic and zdump commands.
 5083 
 5084   changes to overflow/underflow checking in zic
 5085 
 5086   a localtime typo fix.
 5087 
 5088   Update the leapseconds and tz-art.htm files.
 5089 
 5090 
 5091 Release 2003a - 2003-03-24 09:30:54 -0500
 5092 
 5093   changes by Paul Eggert
 5094 
 5095   a few additions and modifications to the tz-art.htm file
 5096 
 5097 
 5098 Release 2002d - 2002-10-15 13:12:42 -0400
 5099 
 5100   changes by Paul Eggert, less the "Britain (UK)" change in iso3166.tab
 5101 
 5102   There's also a new time zone quote in "tz-art.htm".
 5103 
 5104 
 5105 Release 2002c - 2002-04-04 11:55:20 -0500
 5106 
 5107   changes by Paul Eggert
 5108 
 5109   Change zic.c to avoid creating symlinks to files that don't exist.
 5110 
 5111 
 5112 Release 2002b - 2002-01-28 12:56:03 -0500
 5113 
 5114   [These change notes are for Release 2002a, which was corrupted.
 5115   2002b was a corrected version of 2002a.]
 5116 
 5117   changes by Paul Eggert
 5118 
 5119   Update the "leapseconds" file to note that there'll be no leap
 5120   second at the end of June, 2002.
 5121 
 5122   Change "zic.c" to deal with a problem in handling the "Asia/Bishkek" zone.
 5123 
 5124   Change to "difftime.c" to avoid sizeof problems.
 5125 
 5126 
 5127 Release 2001d - 2001-10-09 13:31:32 -0400
 5128 
 5129   changes by Paul Eggert
 5130 
 5131 
 5132 Release 2001c - 2001-06-05 13:59:55 -0400
 5133 
 5134   changes by Paul Eggert and Andrew Brown
 5135 
 5136 
 5137 Release 2001b - 2001-04-05 16:44:38 -0400
 5138 
 5139   changes by Paul Eggert (modulo jnorgard's typo fix)
 5140 
 5141   tz-art.htm has been HTMLified.
 5142 
 5143 
 5144 Release 2001a - 2001-03-13 12:57:44 -0500
 5145 
 5146   changes by Paul Eggert
 5147 
 5148   An addition to the "leapseconds" file: comments with the text of the
 5149   latest IERS leap second notice.
 5150 
 5151   Trailing white space has been removed from data file lines, and
 5152   repeated spaces in "Rule Jordan" lines in the "asia" file have been
 5153   converted to tabs.
 5154 
 5155 
 5156 Release 2000h - 2000-12-14 15:33:38 -0500
 5157 
 5158   changes by Paul Eggert
 5159 
 5160   one typo fix in the "art" file
 5161 
 5162   With providence, this is the last update of the millennium.
 5163 
 5164 
 5165 Release 2000g - 2000-10-10 11:35:22 -0400
 5166 
 5167   changes by Paul Eggert
 5168 
 5169   correction of John Mackin's name submitted by Robert Elz
 5170 
 5171   Garry Shandling's Daylight Saving Time joke (!?!) from the recent
 5172   Emmy Awards broadcast.
 5173 
 5174 
 5175 Release 2000f - 2000-08-10 09:31:58 -0400
 5176 
 5177   changes by Paul Eggert
 5178 
 5179   Added information in "tz-art.htm" on a Seinfeld reference to DST.
 5180 
 5181   Error checking and messages in the "yearistype" script have been
 5182   improved.
 5183 
 5184 
 5185 Release 2000e - 2000-07-31 09:27:54 -0400
 5186 
 5187   data changes by Paul Eggert
 5188 
 5189   a change to the default value of the defined constant HAVE_STRERROR
 5190 
 5191   the addition of a Dave Barry quote on DST to the tz-arts file
 5192 
 5193 
 5194 Release 2000d - 2000-04-20 15:43:04 -0400
 5195 
 5196   changes to the documentation and code of strftime for C99 conformance
 5197 
 5198   a bug fix for date.c
 5199 
 5200   These are based on (though modified from) changes by Paul Eggert.
 5201 
 5202 
 5203 Release 2000c - 2000-03-04 10:31:43 -0500
 5204 
 5205   changes by Paul Eggert
 5206 
 5207 
 5208 Release 2000b - 2000-02-21 12:16:29 -0500
 5209 
 5210   changes by Paul Eggert and Joseph Myers
 5211 
 5212   modest tweaks to the tz-art.htm and tz-link.htm files
 5213 
 5214 
 5215 Release 2000a - 2000-01-18 09:21:26 -0500
 5216 
 5217   changes by Paul Eggert
 5218 
 5219   The two hypertext documents have also been renamed.
 5220 
 5221 
 5222 Release code1999i-data1999j - 1999-11-15 18:43:22 -0500
 5223 
 5224   Paul Eggert's changes
 5225 
 5226   additions to the "zic" manual page and the "Arts.htm" file
 5227 
 5228 
 5229 Release code1999h-data1999i - 1999-11-08 14:55:21 -0500
 5230 
 5231   [not summarized]
 5232 
 5233 
 5234 Release data1999h - 1999-10-07 03:50:29 -0400
 5235 
 5236   changes by Paul Eggert to "europe" (most importantly, fixing
 5237   Lithuania and Estonia)
 5238 
 5239 
 5240 Release 1999g - 1999-09-28 11:06:18 -0400
 5241 
 5242   data changes by Paul Eggert (most importantly, the change for
 5243   Lebanon that buys correctness for this coming Sunday)
 5244 
 5245   The "code" file contains changes to "Makefile" and "checktab.awk" to
 5246   allow better checking of time zone files before they are published.
 5247 
 5248 
 5249 Release 1999f - 1999-09-23 09:48:14 -0400
 5250 
 5251   changes by Arthur David Olson and Paul Eggert
 5252 
 5253 
 5254 Release 1999e - 1999-08-17 15:20:54 -0400
 5255 
 5256   changes circulated by Paul Eggert, although the change to handling
 5257   of DST-specifying timezone names has been commented out for now
 5258   (search for "XXX" in "localtime.c" for details).  These files also
 5259   do not make any changes to the start of DST in Brazil.
 5260 
 5261   In addition to Paul's changes, there are updates to "Arts.htm" and
 5262   cleanups of URLs.
 5263 
 5264 
 5265 Release 1999d - 1999-03-30 11:31:07 -0500
 5266 
 5267   changes by Paul Eggert
 5268 
 5269   The Makefile's "make public" rule has also been changed to do a test
 5270   compile of each individual time zone data file (which should help
 5271   avoid problems such as the one we had with Nicosia).
 5272 
 5273 
 5274 Release 1999c - 1999-03-25 09:47:47 -0500
 5275 
 5276   changes by Paul Eggert, most importantly the change for Chile.
 5277 
 5278 
 5279 Release 1999b - 1999-02-01 17:51:44 -0500
 5280 
 5281   changes by Paul Eggert
 5282 
 5283   code changes (suggested by Mani Varadarajan, mani at be.com) for
 5284   correct handling of symbolic links when building using a relative directory
 5285 
 5286   code changes to generate correct messages for failed links
 5287 
 5288   updates to the URLs in Arts.htm
 5289 
 5290 
 5291 Release 1999a - 1999-01-19 16:20:29 -0500
 5292 
 5293   error message internationalizations and corrections in zic.c and
 5294   zdump.c (as suggested by Vladimir Michl, vladimir.michl at upol.cz,
 5295   to whom thanks!)
 5296 
 5297 
 5298 Release code1998h-data1998i - 1998-10-01 09:56:10 -0400
 5299 
 5300   changes for Brazil, Chile, and Germany
 5301 
 5302   support for use of "24:00" in the input files for the time zone compiler
 5303 
 5304 
 5305 Release code1998g-data1998h - 1998-09-24 10:50:28 -0400
 5306 
 5307   changes by Paul Eggert
 5308 
 5309   correction to a define in the "private.h" file
 5310 
 5311 
 5312 Release data1998g - 1998-08-11 03:28:35 -0000
 5313   [tzdata1998g.tar.gz is missing!]
 5314 
 5315   Lithuanian change provided by mgedmin at pub.osf.it
 5316 
 5317   Move creation of the GMT link with Etc/GMT to "etcetera" (from
 5318   "backward") to ensure that the GMT file is created even where folks
 5319   don't want the "backward" links (as suggested by Paul Eggert).
 5320 
 5321 
 5322 Release data1998f - 1998-07-20 13:50:00 -0000
 5323   [tzdata1998f.tar.gz is missing!]
 5324 
 5325   Update the "leapseconds" file to include the newly-announced
 5326   insertion at the end of 1998.
 5327 
 5328 
 5329 Release code1998f - 1998-06-01 10:18:31 -0400
 5330 
 5331   addition to localtime.c by Guy Harris
 5332 
 5333 
 5334 Release 1998e - 1998-05-28 09:56:26 -0400
 5335 
 5336   The Makefile is changed to produce zoneinfo-posix rather than
 5337   zoneinfo/posix, and to produce zoneinfo-leaps rather than
 5338   zoneinfo/right.
 5339 
 5340   data changes by Paul Eggert
 5341 
 5342   changes from Guy Harris to provide asctime_r and ctime_r
 5343 
 5344   A usno1998 file (substantially identical to usno1997) has been added.
 5345 
 5346 
 5347 Release 1998d - 1998-05-14 11:58:34 -0400
 5348 
 5349   changes to comments (in particular, elimination of references to CIA maps).
 5350   "Arts.htm", "WWW.htm", "asia", and "australasia" are the only places
 5351   where changes occur.
 5352 
 5353 
 5354 Release 1998c - 1998-02-28 12:32:26 -0500
 5355 
 5356   changes by Paul Eggert (save the "French correction," on which I'll
 5357   wait for the dust to settle)
 5358 
 5359   symlink changes
 5360 
 5361   changes and additions to Arts.htm
 5362 
 5363 
 5364 Release 1998b - 1998-01-17 14:31:51 -0500
 5365 
 5366   URL cleanups and additions
 5367 
 5368 
 5369 Release 1998a - 1998-01-13 12:37:35 -0500
 5370 
 5371   changes by Paul Eggert
 5372 
 5373 
 5374 Release code1997i-data1997k - 1997-12-29 09:53:41 -0500
 5375 
 5376   changes by Paul Eggert, with minor modifications from Arthur David
 5377   Olson to make the files more browser friendly
 5378 
 5379 
 5380 Release code1997h-data1997j - 1997-12-18 17:47:35 -0500
 5381 
 5382   minor changes to put "TZif" at the start of each timezone information file
 5383 
 5384   a rule has also been added to the Makefile so you can
 5385 	make zones
 5386   to just recompile the zone information files (rather than doing a
 5387   full "make install" with its other effects).
 5388 
 5389 
 5390 Release data1997i - 1997-10-07 08:45:38 -0400
 5391 
 5392   changes to Africa by Paul Eggert
 5393 
 5394 
 5395 Release code1997g-data1997h - 1997-09-04 16:56:54 -0400
 5396 
 5397   corrections for Uruguay (and other locations)
 5398 
 5399   Arthur David Olson's simple-minded fix allowing mktime to both
 5400   correctly handle leap seconds and correctly handle tm_sec values
 5401   upon which arithmetic has been performed.
 5402 
 5403 
 5404 Release code1997f-data1997g - 1997-07-19 13:15:02 -0400
 5405 
 5406   Paul Eggert's updates
 5407 
 5408   a small change to a function prototype;
 5409 
 5410   "Music" has been renamed "Arts.htm", HTMLified, and augmented to
 5411   include information on Around the World in Eighty Days.
 5412 
 5413 
 5414 Release code1997e-data1997f - 1997-05-03 18:52:34 -0400
 5415 
 5416   fixes to zic's error handling
 5417 
 5418   changes inspired by the item circulated on Slovenia
 5419 
 5420   The description of Web resources has been HTMLified for browsing
 5421   convenience.
 5422 
 5423   A new piece of tz-related music has been added to the "Music" file.
 5424 
 5425 
 5426 Release code1997d-data1997e - 1997-03-29 12:48:52 -0500
 5427 
 5428   Paul Eggert's latest suggestions
 5429 
 5430 
 5431 Release code1997c-data1997d - 1997-03-07 20:37:54 -0500
 5432 
 5433   changes to "zic.c" to correct performance of the "-s" option
 5434 
 5435   a new file "usno1997"
 5436 
 5437 
 5438 Release data1997c - 1997-03-04 09:58:18 -0500
 5439 
 5440   changes in Israel
 5441 
 5442 
 5443 Release 1997b - 1997-02-27 18:34:19 -0500
 5444 
 5445   The data file incorporates the 1997 leap second.
 5446 
 5447   The code file incorporates Arthur David Olson's take on the
 5448   zic/multiprocessor/directory-creation situation.
 5449 
 5450 
 5451 Release 1997a - 1997-01-21 09:11:10 -0500
 5452 
 5453   Paul Eggert's Antarctica (and other changes)
 5454 
 5455   Arthur David Olson finessed the "getopt" issue by checking against
 5456   both -1 and EOF (regardless of POSIX, SunOS 4.1.1's manual says -1
 5457   is returned while SunOS 5.5's manual says EOF is returned).
 5458 
 5459 
 5460 Release code1996o-data1996n - 1996-12-27 21:42:05 -0500
 5461 
 5462   Paul Eggert's latest changes
 5463 
 5464 
 5465 Release code1996n - 1996-12-16 09:42:02 -0500
 5466 
 5467   link snapping fix from Bruce Evans (via Garrett Wollman)
 5468 
 5469 
 5470 Release data1996m - 1996-11-24 02:37:34 -0000
 5471   [tzdata1996m.tar.gz is missing!]
 5472 
 5473   Paul Eggert's batch of changes
 5474 
 5475 
 5476 Release code1996m-data1996l - 1996-11-05 14:00:12 -0500
 5477 
 5478   No functional changes here; the files have simply been changed to
 5479   make more use of ISO style dates in comments. The names of the above
 5480   files now include the year in full.
 5481 
 5482 
 5483 Release code96l - 1996-09-08 17:12:20 -0400
 5484 
 5485   tzcode96k was missing a couple of pieces.
 5486 
 5487 
 5488 Release 96k - 1996-09-08 16:06:22 -0400
 5489 
 5490   the latest round of changes from Paul Eggert
 5491 
 5492   the recent Year 2000 material
 5493 
 5494 
 5495 Release code96j - 1996-07-30 13:18:53 -0400
 5496 
 5497   Set sp->typecnt as suggested by Timothy Patrick Murphy.
 5498 
 5499 
 5500 Release code96i - 1996-07-27 20:11:35 -0400
 5501 
 5502   Paul's suggested patch for strftime %V week numbers
 5503 
 5504 
 5505 Release data96i - 1996-07-01 18:13:04 -0400
 5506 
 5507   "northamerica" and "europe" changes by Paul Eggert
 5508 
 5509 
 5510 Release code96h - 1996-06-05 08:02:21 -0400
 5511 
 5512   fix for handling transitions specified in Universal Time
 5513 
 5514   Some "public domain" notices have also been added.
 5515 
 5516 
 5517 Release code96g - 1996-05-16 14:00:26 -0400
 5518 
 5519   fix for the simultaneous-DST-and-zone-change challenge
 5520 
 5521 
 5522 Release data96h - 1996-05-09 17:40:51 -0400
 5523 
 5524   changes by Paul Eggert
 5525 
 5526 
 5527 Release code96f-data96g - 1996-05-03 03:09:59 -0000
 5528   [tzcode96f.tar.gz + tzdata96g.tar.gz are both missing!]
 5529 
 5530   The changes get us some of the way to fixing the problems noted in Paul
 5531   Eggert's letter yesterday (in addition to a few others).  The approach
 5532   has been to make zic a bit smarter about figuring out what time zone
 5533   abbreviations apply just after the time specified in the "UNTIL" part
 5534   of a zone line.  Putting the smarts in zic means avoiding having
 5535   transition times show up in both "Zone" lines and "Rule" lines, which
 5536   in turn avoids multiple transition time entries in time zone files.
 5537   (This also makes the zic input files such as "europe" a bit shorter and
 5538   should ease maintenance.)
 5539 
 5540 
 5541 Release data96f - 1996-04-19 19:20:03 -0000
 5542   [tzdata96f.tar.gz is missing!]
 5543 
 5544   The only changes are to the "northamerica" file; the time zone
 5545   abbreviation for Denver is corrected to MST (and MDT), and the
 5546   comments for Mexico have been updated.
 5547 
 5548 
 5549 Release data96e - 1996-03-19 17:37:26 -0500
 5550 
 5551   Proposals by Paul Eggert, in particular the Portugal change that
 5552   comes into play at the end of this month.
 5553 
 5554 
 5555 Release data96d - 1996-03-18 20:49:39 -0500
 5556 
 5557   [not summarized]
 5558 
 5559 
 5560 Release code96e - 1996-02-29 15:43:27 -0000
 5561   [tzcode96e.tar.gz is missing!]
 5562 
 5563   internationalization changes and the fix to the documentation for strftime
 5564 
 5565 
 5566 Release code96d-data96c - 1996-02-12 11:05:27 -0500
 5567 
 5568   The "code" file simply updates Bob Kridle's electronic address.
 5569 
 5570   The "data" file updates rules for Mexico.
 5571 
 5572 
 5573 Release data96b - 1996-01-27 15:44:42 -0500
 5574 
 5575   Kiribati change
 5576 
 5577 
 5578 Release code96c - 1996-01-16 16:58:15 -0500
 5579 
 5580   leap-year streamlining and binary-search changes
 5581 
 5582   fix to newctime.3
 5583 
 5584 
 5585 Release code96b - 1996-01-10 20:42:39 -0500
 5586 
 5587   fixes and enhancements from Paul Eggert, including code that
 5588   emulates the behavior of recent versions of the SunOS "date"
 5589   command.
 5590 
 5591 
 5592 Release 96a - 1996-01-06 09:08:24 -0500
 5593 
 5594   Israel updates
 5595 
 5596   fixes to strftime.c for correct ISO 8601 week number generation,
 5597   plus support for two new formats ('G' and 'g') to give ISO 8601 year
 5598   numbers (which are not necessarily the same as calendar year numbers)
 5599 
 5600 
 5601 Release code95i-data95m - 1995-12-21 12:46:47 -0500
 5602 
 5603   The latest revisions from Paul Eggert are included, the usno1995
 5604   file has been updated, and a new file ("WWW") covering useful URLs
 5605   has been added.
 5606 
 5607 
 5608 Release code95h-data95l - 1995-12-19 18:10:12 -0500
 5609 
 5610   A simplification of a macro definition, a change to data for Sudan,
 5611   and (for last minute shoppers) notes in the "Music" file on the CD
 5612   "Old Man Time".
 5613 
 5614 
 5615 Release code95g-data95k - 1995-10-30 10:32:47 -0500
 5616 
 5617   (slightly reformatted) 8-bit-clean proposed patch
 5618 
 5619   minor patch: US/Eastern -> America/New_York
 5620 
 5621   snapshot of the USNO's latest data ("usno1995")
 5622 
 5623   some other minor cleanups
 5624 
 5625 
 5626 Release code95f-data95j - 1995-10-28 21:01:34 -0000
 5627   [tzcode95f.tar.gz + tzdata95j.tar.gz are both missing!]
 5628 
 5629   European cleanups
 5630 
 5631   support for 64-bit time_t's
 5632 
 5633   optimization in localtime.c
 5634 
 5635 
 5636 Release code95e - 1995-10-13 13:23:57 -0400
 5637 
 5638   the mktime change to scan from future to past when trying to find time zone
 5639   offsets
 5640 
 5641 
 5642 Release data95i - 1995-09-26 10:43:26 -0400
 5643 
 5644   For Canada/Central, guess that the Sun customer's "one week too
 5645   early" was just a approximation, and the true error is one month
 5646   too early.  This is consistent with the rest of Canada.
 5647 
 5648 
 5649 Release data95h - 1995-09-21 11:26:48 -0400
 5650 
 5651   latest changes from Paul Eggert
 5652 
 5653 
 5654 Release code95d - 1995-09-14 11:14:45 -0400
 5655 
 5656   the addition of a "Music" file, which documents four recorded
 5657   versions of the tune "Save That Time".
 5658 
 5659 
 5660 Release data95g - 1995-09-01 17:21:36 -0400
 5661 
 5662   "yearistype" correction
 5663 
 5664 
 5665 Release data95f - 1995-08-28 20:46:56 -0400
 5666 
 5667   Paul Eggert's change to the australasia file
 5668 
 5669 
 5670 Release data95e - 1995-07-08 18:02:34 -0400
 5671 
 5672   The only change is a leap second at the end of this year.
 5673   Thanks to Bradley White for forwarding news on the leap second.
 5674 
 5675 
 5676 Release data95d - 1995-07-03 13:26:22 -0400
 5677 
 5678   Paul Eggert's changes
 5679 
 5680 
 5681 Release data95c - 1995-07-02 19:19:28 -0400
 5682 
 5683   changes to "asia", "backward", "europe", and "southamerica"
 5684   (read: northamericacentrics need not apply)
 5685 
 5686 
 5687 Release code95c - 1995-03-13 14:00:46 -0500
 5688 
 5689   one-line fix for sign extension problems in detzcode
 5690 
 5691 
 5692 Release 95b - 1995-03-04 11:22:38 -0500
 5693 
 5694   Minor changes in both:
 5695 
 5696   The "code" file contains a workaround for the lack of "unistd.h" in
 5697   Microsoft C++ version 7.
 5698 
 5699   The "data" file contains a fixed "Link" for America/Shiprock.
 5700 
 5701 
 5702 Release 94h - 1994-12-10 12:51:14 -0500
 5703 
 5704   The files:
 5705 
 5706   *	incorporate the changes to "zdump" and "date" to make changes to
 5707 	the "TZ" environment variable permanent;
 5708 
 5709   *	incorporate the table changes by Paul Eggert;
 5710 
 5711   *	include (and document) support for universal time specifications in
 5712 	data files - but do not (yet) include use of this feature in the
 5713 	data files.
 5714 
 5715   Think of this as "TZ Classic" - the software has been set up not to break if
 5716   universal time shows up in its input, and data entries have been
 5717   left as is so as not to break existing implementations.
 5718 
 5719 
 5720 Release data94f - 1994-08-20 12:56:09 -0400
 5721 
 5722   (with thanks!) the latest data updates from Paul Eggert
 5723 
 5724 
 5725 Release data94e - 1994-06-04 13:13:53 -0400
 5726 
 5727   [not summarized]
 5728 
 5729 
 5730 Release code94g - 1994-05-05 12:14:07 -0400
 5731 
 5732   fix missing "optind.c" and a reference to it in the Makefile
 5733 
 5734 
 5735 Release code94f - 1994-05-05 13:00:33 -0000
 5736   [tzcode94f.tar.gz is missing!]
 5737 
 5738   changes to avoid overflow in difftime, as well as changes to cope
 5739   with the 52/53 challenge in strftime
 5740 
 5741 
 5742 Release code94e - 1994-03-30 23:32:59 -0500
 5743 
 5744   change for the benefit of PCTS
 5745 
 5746 
 5747 Release 94d - 1994-02-24 15:42:25 -0500
 5748 
 5749   Avoid clashes with POSIX semantics for zones such as GMT+4.
 5750 
 5751   Some other very minor housekeeping is also present.
 5752 
 5753 
 5754 Release code94c - 1994-02-10 08:52:40 -0500
 5755 
 5756   Fix bug where mkdirs was broken unless you compile with
 5757   -fwritable-strings (which is generally losing to do).
 5758 
 5759 
 5760 Release 94b - 1994-02-07 10:04:33 -0500
 5761 
 5762   work by Paul Eggert who notes:
 5763 
 5764   I found another book of time zone histories by E W Whitman; it's not
 5765   as extensive as Shanks but has a few goodies of its own.  I used it
 5766   to update the tables.  I also fixed some more as a result of
 5767   correspondence with Adam David and Peter Ilieve, and move some stray
 5768   links from 'europe' to 'backward'.  I corrected some scanning errors
 5769   in usno1989.
 5770 
 5771   As far as the code goes, I fixed zic to allow years in the range
 5772   INT_MIN to INT_MAX; this fixed a few boundary conditions around 1900.
 5773   And I cleaned up the zic documentation a little bit.
 5774 
 5775 
 5776 Release data94a - 1994-02-03 08:58:54 -0500
 5777 
 5778   It simply incorporates the recently announced leap second into the
 5779   "leapseconds" file.
 5780 
 5781 
 5782 Release 93g - 1993-11-22 17:28:27 -0500
 5783 
 5784   Paul Eggert has provided a good deal of historic information (based
 5785   on Shanks), and there are some code changes to deal with the buglets
 5786   that crawled out in dealing with the new information.
 5787 
 5788 
 5789 Release 93f - 1993-10-15 12:27:46 -0400
 5790 
 5791   Paul Eggert's changes
 5792 
 5793 
 5794 Release 93e - 1993-09-05 21:21:44 -0400
 5795 
 5796   This has updated data for Israel, England, and Kwajalein.  There's
 5797   also an update to "zdump" to cope with Kwajalein's 24-hour jump.
 5798   Thanks to Paul Eggert and Peter Ilieve for the changes.
 5799 
 5800 
 5801 Release 93d - 1993-06-17 23:34:17 -0400
 5802 
 5803   new fix and new data on Israel
 5804 
 5805 
 5806 Release 93c - 1993-06-06 19:31:55 -0400
 5807 
 5808   [not summarized]
 5809 
 5810 
 5811 Release 93b - 1993-02-02 14:53:58 -0500
 5812 
 5813   updated "leapseconds" file
 5814 
 5815 
 5816 Release 93 - 1993-01-08 07:01:06 -0500
 5817 
 5818   At kre's suggestion, the package has been split in two - a code piece
 5819   (which also includes documentation) that's only of use to folks who
 5820   want to recompile things and a data piece useful to anyone who can
 5821   run "zic".
 5822 
 5823   The new version has a few changes to the data files, a few
 5824   portability changes, and an off-by-one fix (with thanks to
 5825   Tom Karzes at deshaw.com for providing a description and a
 5826   solution).
 5827 
 5828 
 5829 Release 92c - 1992-11-21 17:35:36 -0000
 5830   [tz92c.tar.Z is missing!]
 5831 
 5832   The fallout from the latest round of DST transitions.
 5833 
 5834   There are changes for Portugal, Saskatchewan, and "Pacific-New";
 5835   there's also a change to "zic.c" that makes it portable to more systems.
 5836 
 5837 
 5838 Release 92 - 1992-04-25 18:17:03 -0000
 5839   [tz92.tar.Z is missing!]
 5840 
 5841   By popular demand (well, at any rate, following a request by kre at munnari)
 5842 
 5843 
 5844 The 1989 update of the time zone package featured:
 5845 
 5846   *	POSIXization (including interpretation of POSIX-style TZ environment
 5847 	variables, provided by Guy Harris),
 5848   *	ANSIfication (including versions of "mktime" and "difftime"),
 5849   *	SVIDulation (an "altzone" variable)
 5850   *	MACHination (the "gtime" function)
 5851   *	corrections to some time zone data (including corrections to the rules
 5852 	for Great Britain and New Zealand)
 5853   *	reference data from the United States Naval Observatory for folks who
 5854 	want to do additional time zones
 5855   *	and the 1989 data for Saudi Arabia.
 5856 
 5857   (Since this code will be treated as "part of the implementation" in some
 5858   places and as "part of the application" in others, there's no good way to
 5859   name functions, such as timegm, that are not part of the proposed ANSI C
 5860   standard; such functions have kept their old, underscore-free names in this
 5861   update.)
 5862 
 5863   And the "dysize" function has disappeared; it was present to allow
 5864   compilation of the "date" command on old BSD systems, and a version of "date"
 5865   is now provided in the package.  The "date" command is not created when you
 5866   "make all" since it may lack options provided by the version distributed with
 5867   your operating system, or may not interact with the system in the same way
 5868   the native version does.
 5869 
 5870   Since POSIX frowns on correct leap second handling, the default behavior of
 5871   the "zic" command (in the absence of a "-L" option) has been changed to omit
 5872   leap second information from its output files.
 5873 
 5874 
 5875 -----
 5876 Notes
 5877 
 5878 This file contains copies of the part of each release announcement
 5879 that talks about the changes in that release.  The text has been
 5880 adapted and reformatted for the purposes of this file.
 5881 
 5882 Traditionally a release R consists of a pair of tarball files,
 5883 tzcodeR.tar.gz and tzdataR.tar.gz.  However, some releases (e.g.,
 5884 code2010a, data2012c) consist of just one or the other tarball, and a
 5885 few (e.g., code2012c-data2012d) have tarballs with mixed version
 5886 numbers.  Recent releases also come in an experimental format
 5887 consisting of a single tarball tzdb-R.tar.lz with extra data.
 5888 
 5889 Release timestamps are taken from the release's commit (for newer,
 5890 Git-based releases), from the newest file in the tarball (for older
 5891 releases, where this info is available) or from the email announcing
 5892 the release (if all else fails; these are marked with a time zone
 5893 abbreviation of -0000 and an "is missing!" comment).
 5894 
 5895 Earlier versions of the code and data were not announced on the tz
 5896 list and are not summarized here.
 5897 
 5898 This file is in the public domain.
 5899 
 5900 Local Variables:
 5901 coding: utf-8
 5902 End: