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  1. JDK
  2. JDK-8228469

(tz) Upgrade Timezone Data to tzdata2019b



    • b09
    • generic
    • generic



        [Tue Jul 2 00:28:10 UTC 2019]

        The 2019b release of the tz code and data is available. It reflects the
        following changes, which were either circulated on the tz mailing list
        or are relatively minor technical or administrative changes:

             Brazil no longer observes DST.
             'zic -b slim' outputs smaller TZif files; please try it out.
             Palestine's 2019 spring-forward transition was on 03-29, not 03-30.

           Changes to future timestamps

             Brazil has canceled DST and will stay on standard time indefinitely.
             (Thanks to Steffen Thorsen, Marcus Diniz, and Daniel Soares de

             Predictions for Morocco now go through 2087 instead of 2037, to
             work around a problem on newlib when using TZif files output by
             zic 2019a or earlier. (Problem reported by David Gauchard.)

           Changes to past and future timestamps

             Palestine's 2019 spring transition was 03-29 at 00:00, not 03-30
             at 01:00. (Thanks to Sharef Mustafa and Even Scharning.) Guess
             future transitions to be March's last Friday at 00:00.

           Changes to past timestamps

             Hong Kong's 1941-06-15 spring-forward transition was at 03:00, not
             03:30. Its 1945 transition from JST to HKT was on 11-18 at 02:00,
             not 09-15 at 00:00. In 1946 its spring-forward transition was on
             04-21 at 00:00, not the previous day at 03:30. From 1946 through
             1952 its fall-back transitions occurred at 04:30, not at 03:30.
             In 1947 its fall-back transition was on 11-30, not 12-30.
             (Thanks to P Chan.)

           Changes to past time zone abbreviations

             Italy's 1866 transition to Rome Mean Time was on December 12, not
             September 22. This affects only the time zone abbreviation for
             Europe/Rome between those dates. (Thanks to Stephen Trainor and
             Luigi Rosa.)

           Changes affecting metadata only

             Add info about the Crimea situation in zone1970.tab and zone.tab.
             (Problem reported by Serhii Demediuk.)

           Changes to code

             zic's new -b option supports a way to control data bloat and to
             test for year-2038 bugs in software that reads TZif files.
             'zic -b fat' and 'zic -b slim' generate larger and smaller output;
             for example, changing from fat to slim shrinks the Europe/London
             file from 3648 to 1599 bytes, saving about 56%. Fat and slim
             files represent the same set of timestamps and use the same TZif
             format as documented in tzfile(5) and in Internet RFC 8536.
             Fat format attempts to work around bugs or incompatibilities in
             older software, notably software that mishandles 64-bit TZif data
             or uses obsolete TZ strings like "EET-2EEST" that lack DST rules.
             Slim format is more efficient and does not work around 64-bit bugs
             or obsolete TZ strings. Currently zic defaults to fat format
             unless you compile with -DZIC_BLOAT_DEFAULT=\"slim\"; this
             out-of-the-box default is intended to change in future releases
             as the buggy software often mishandles timestamps anyway.

             zic no longer treats a set of rules ending in 2037 specially.
             Previously, zic assumed that such a ruleset meant that future
             timestamps could not be predicted, and therefore omitted a
             POSIX-like TZ string in the TZif output. The old behavior is no
             longer needed for current tzdata, and caused problems with newlib
             when used with older tzdata (reported by David Gauchard).

             zic no longer generates some artifact transitions. For example,
             Europe/London no longer has a no-op transition in January 1996.

           Changes to build procedure

             tzdata.zi now assumes zic 2017c or later. This shrinks tzdata.zi
             by a percent or so.

           Changes to documentation and commentary

             The Makefile now documents the POSIXRULES macro as being obsolete,
             and similarly, zic's -p POSIXRULES option is now documented as
             being obsolete. Although the POSIXRULES feature still exists and
             works as before, in practice it is rarely used for its intended
             purpose, and it does not work either in the default reference
             implementation (for timestamps after 2037) or in common
             implementations such as GNU/Linux (for contemporary timestamps).
             Since POSIXRULES was designed primarily as a temporary transition
             facility for System V platforms that died off decades ago, it is
             being decommissioned rather than institutionalized.

             New info on Bonin Islands and Marcus (thanks to Wakaba and Phake

        Here are links to the release files:


        Links are also available via plain HTTP, and via FTP from
        ftp://ftp.iana.org/tz/releases with the same basenames as above.

        PS. If your tzdata parser does not yet support negative DST offsets or
        times past 24:00, this release's data entries can be turned into a
        rearguard-format tarball that does not use these features. This is
        intended to be a temporary transition aid for these parsers. To generate
        a rearguard-format tarball, obtain the full distribution as described
        above, and run the command 'make rearguard_tarballs' on a development
        host. Or you can run 'make rearguard.zi' to generate a single file that
        can be fed directly to a parser that works like 'zic'.


          Issue Links

            TZ: 2019b Sub-task Closed Unassigned 2019-07-01



                rpatil Ramanand Patil (Inactive)
                rpatil Ramanand Patil (Inactive)
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