[tz-announce] 2026b release of tz code and data available

April 23, 2026

      The 2026b release of the tz code and data is available. As Tim mentioned 
yesterday[1], this release’s main impetus is British Columbia’s decision 
to stop changing its clocks and stay on permanent UTC-07, which affects 
BC’s UTC offsets starting 2026-11-01 at 02:00. Since this change will 
likely cause problems downstream as CLDR’s latest release cannot handle 
it, we’re pushing out this release now so that downstream has some time 
to test and reprogram. Quite possibly we’ll need another release soon to 
accommodate proposed changes in Alberta and Northwest Territories.

[1]: 
https://lists.iana.org/hyperkitty/list/tz@iana.org/thread/LZIJFAY2K4OXXCAGFM...

There is an embarrassing typo in the 2026b release: its NEWS file's 
third line has the wrong release number. I applied the following patch 
to the development version on GitHub and this patch should appear in the 
2026c release.

   diff --git a/NEWS b/NEWS
   index a0042701..ea52e67e 100644
   --- a/NEWS
   +++ b/NEWS
   @@ -3 +3 @@ News for the tz database
   -Release 2026a - 2026-04-22 23:06:43 -0700
   +Release 2026b - 2026-04-22 23:06:43 -0700

The 2026b release contains the following changes:

   Briefly:
     British Columbia moved to permanent -07 on 2026-03-09.
     Some more overflow bugs have been fixed in zic.

   Changes to future timestamps

     British Columbia’s 2026-03-08 spring forward was its last
     foreseeable clock change, as it moved to permanent -07 thereafter.
     (Thanks to Arthur David Olson.)  Although the change to permanent
     -07 legally took place on 2026-03-09, temporarily model the change
     to occur on 2026-11-01 at 02:00 instead.  This works around a
     limitation in CLDR v48.2 (2026-03-17).  This temporary hack is
     planned to be removed after CLDR is fixed.

   Changes to code

     zic no longer mishandles a last transition to a new time type.

     zic no longer overflows a buffer when generating a TZ string like
     "PST-167:59:58PDT-167:59:59,M11.5.6/-167:59:59,M12.5.6/-167:59:59",
     which can occur with adversarial input.  (Thanks to Naveed Khan.)

     zic no longer generates a longer TZif file than necessary when
     an earlier time zone abbreviation is a suffix of a later one.
     As a nice side effect, zic no longer overflows a buffer when given
     a long series of abbreviations, each a suffix of the next.
     (Buffer overflow reported by Arthur Chan.)

     zic no longer overflows an int when processing input like ‘Zone
     Ouch 2147483648:00:00 - LMT’.  The int overflow can lead to buffer
     overflow in adversarial cases.  (Thanks to Naveed Khan.)

     zic now checks for signals more often.

Here are links to the release files:

   https://www.iana.org/time-zones/repository/releases/tzcode2026b.tar.gz
   https://www.iana.org/time-zones/repository/releases/tzdata2026b.tar.gz
   https://www.iana.org/time-zones/repository/releases/tzdb-2026b.tar.lz

The following convenience links are also available, although they may 
point to the previous release until the relevant caches are refreshed:

   https://www.iana.org/time-zones/repository/tzcode-latest.tar.gz
   https://www.iana.org/time-zones/repository/tzdata-latest.tar.gz
   https://www.iana.org/time-zones/repository/tzdb-latest.tar.lz

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

Each release file has a GPG signature, which can be retrieved by 
appending ".asc" to the above URLs. Copies of these signatures are 
appended to this message.

This release corresponds to commit 
48c25a1ba86cb602990c0573aba7795417931bb4 dated 2026-04-22 23:06:43 -0700 
and tagged '2026b' in the development GitHub repository at 
<https://github.com/eggert/tz>.

Here are the SHA-512 checksums for the release files:

55b44d52a83c9db151be32c3d78376ea7f9d4311ef15ed6fe34b855b08fc546531e51309d178d9c175a6d5d7d0b058440e45a55d200ca8925e3798dac9bc739f 
  tzcode2026b.tar.gz
a44882258c0a7fbe587e8b73d6bb3cd5be7d4788976ea742adbbf176eb3b33e5bd7d1714b2fffe2972b1a42e7335eac39ed0bd63e819bb421550f8cae1df4f2f 
  tzdata2026b.tar.gz
5ec7f74f14cd2c70a0730e3690e82bd0ba889ac26c96397c16aa08005473c2c86feb47958b52e0301810c8eb908e6d8faf998ffae75b2337a912cc9e52c0f9e9 
  tzdb-2026b.tar.lz

Here are GPG digital signatures for the release files:

Paul Eggert via tz-announce

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