June 2025 - tz - lists.iana.org

Should all IDs from backzone be available in backward?
by robertbastian＠unicode.org July 2, 2025

July 2, 2025

The set of IDs (zones and links) in backzone is _almost_ a subset of the IDs in backward; the only ID that is in backzone but not in backward is Asia/Hanoi. Can Asia/Hanoi be added as a link in backward to ensure compatibility with systems that use IDs from backzone? Is this a desirable invariant that can be upheld in the future? This was reported to CLDR (https://unicode-org.atlassian.net/browse/CLDR-11977) so it looks like there are systems that are using these IDs.

6 7

Issue with America/Nuuk tz
by Dan Juskevicius June 20, 2025

June 20, 2025

Dear sir or madam, I'm currently working on an issue that one of our customers has reported with the tz database. Using the latest release (2025b), I have been able to reproduce an issue with America/Nuuk time where it reports at -02 instead of -01; I realize that as of 2023-03-25 the America/Nuuk time zone changed its standard time from -03 to -02, but it appears that it is not represented correctly in the tzdb. All other time zones in the database appear to be represented correctly, so I'm trying to narrow down the root cause of the issue but don't know where to look. Has anyone else reported issue with the America/Nuuk tz, and if so, is there a workaround for this? Cheers, Daniel Juskevicius Systems Software Developer djuskevicius(a)qnx.com QNX - It all starts here ---------------------------------------------------------------------- This email and any attachments are intended solely for the use of the individual or entity to whom they are addressed. This email may contain information that is confidential, privileged, or otherwise protected from disclosure. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this email in error, please immediately contact the sender and delete all copies of this email and any attachments from your systems. Any unauthorized review, use, dissemination, distribution, or reproduction of this email by unintended recipients is not authorized and may be unlawful. Thank you for your cooperation.

5 9

TZif Version Selection Issue in tzcode2025b
by PATAN JEELAN BASHA June 11, 2025

June 11, 2025

Hi All, We have encountered an issue after upgrading to tzcode2025b, where zoneinfo files that were previously generated in TZif3 format are now being generated in TZif2 format. This change appears to be due to the removal of the forced version in the writezone() call in zic.c file. Upon investigation, we found that: ->The logic in stringrule() that sets compat = 2013 based on wdayoff is not meaningful in practice. ->For rules like Sun>=8, wdayoff = 0, so compat = 0, and the compiler now generates TZif2. ->This behavior change appears to result from the removal of the forced version and the introduction of dynamic version selection logic. For example, in the northamerica file, we have: Rule US 2007 max - Mar Sun>=8 2:00 1:00 D Rule US 2007 max - Nov Sun>=1 2:00 0 S These rules are used by zones such as America/Chicago and others. Since Sun>=8 results in wdayoff = 0, the compat value remains 0, and the compiler now generates TZif2 instead of TZif3. This change affects all zones relying on similar rules, even though the rule definitions themselves have not changed. Specifically, the change from: writezone(zpfirst->z_name, envvar, ZIC_VERSION); // older code to: writezone(zpfirst->z_name, envvar, version, defaulttype); // new code has caused the compiler to emit TZif2 for rules that previously resulted in TZif3. We believe this logic does not reliably reflect the need for TZif3 and may lead to inconsistent or unexpected output formats. We would appreciate your thoughts on this and whether a patch or enhancement is planned to address it. Best Regards, Jeelan

3 3

Cape Breton Island "time zone"
by Arthur Olson June 10, 2025

June 10, 2025

"Google and Meta search both report that Cape Breton Island has its own time zone 12 minutes ahead of mainland Nova Scotia time because they are both drawing that information from a Beaverton article I wrote in 2024." --Janel Comeau (The Beaverton is a Canadian satire publication. Folks on this mailing list: be alert for Cape Breton Island come 2026-04-01.) --@dashdashado https://www.threads.com/@janelcomeau/post/DKs2YqBJgqK/google-and-meta-searc… https://thebeaverton.com/2024/07/cape-breton-to-create-new-more-annoying-ti…

1 0