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Diffstat (limited to 'NEWS')
| -rw-r--r-- | NEWS | 66 |
1 files changed, 65 insertions, 1 deletions
@@ -1,5 +1,69 @@ News for the tz database +Release 2018e - 2018-05-01 23:42:51 -0700 + + Briefly: + + North Korea switches back to +09 on 2018-05-05. + The main format uses negative DST again, for Ireland etc. + 'make tarballs' now also builds a rearguard tarball. + New 's' and 'd' suffixes in SAVE columns of Rule and Zone lines. + + Changes to past and future time stamps + + North Korea switches back from +0830 to +09 on 2018-05-05. + (Thanks to Kang Seonghoon, Arthur David Olson, Seo Sanghyeon, + and Tim Parenti.) + + Bring back the negative-DST changes of 2018a, except be more + compatible with data parsers that do not support negative DST. + Also, this now affects historical time stamps in Namibia and the + former Czechoslovakia, not just Ireland. The main format now uses + negative DST to model time stamps in Europe/Dublin (from 1971 on), + Europe/Prague (1946/7), and Africa/Windhoek (1994/2017). This + does not affect UT offsets, only time zone abbreviations and the + tm_isdst flag. Also, this does not affect rearguard or vanguard + formats; effectively the main format now uses vanguard instead of + rearguard format. Data parsers that do not support negative DST + can still use data from the rearguard tarball described below. + + Changes to build procedure + + The command 'make tarballs' now also builds the tarball + tzdataVERSION-rearguard.tar.gz, which is like tzdataVERSION.tar.gz + except that it uses rearguard format intended for trailing-edge + data parsers. + + Changes to data format and to code + + The SAVE column of Rule and Zone lines can now have an 's' or 'd' + suffix, which specifies whether the adjusted time is standard time + or daylight saving time. If no suffix is given, daylight saving + time is used if and only if the SAVE column is nonzero; this is + the longstanding behavior. Although this new feature is not used + in tzdata, it could be used to specify the legal time in Namibia + 1994-2017, as opposed to the popular time (see below). + + Changes to past time stamps + + From 1994 through 2017 Namibia observed DST in winter, not summer. + That is, it used negative DST, as Ireland still does. This change + does not affect UTC offsets; it affects only the tm_isdst flag and + the abbreviation used during summer, which is now CAT, not WAST. + Although (as noted by Michael Deckers) summer and winter time were + both simply called "standard time" in Namibian law, in common + practice winter time was considered to be DST (as noted by Stephen + Colebourne). The full effect of this change is only in vanguard + format; in rearguard and main format, the tm_isdst flag is still + zero in winter and nonzero in summer. + + In 1946/7 Czechoslovakia also observed negative DST in winter. + The full effect of this change is only in vanguard format; in + rearguard and main formats, it is modeled as plain GMT without + daylight saving. Also, the dates of some 1944/5 DST transitions + in Czechoslovakia have been changed. + + Release 2018d - 2018-03-22 07:05:46 -0700 Briefly: @@ -39,7 +103,7 @@ Release 2018d - 2018-03-22 07:05:46 -0700 Enderbury and Kiritimati skipped New Year's Eve 1994, not New Year's Day 1995. (Thanks to Kerry Shetline.) - Fix the 1912-01-01 transition for Portugual and its colonies. + Fix the 1912-01-01 transition for Portugal and its colonies. This transition was at 00:00 according to the new UT offset, not according to the old one. Also assume that Cape Verde switched on the same date as the rest, not in 1907. This affects |