Diffstat (limited to 'NEWS')
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
+ 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
@@ -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