On 2026-02-25 03:33, Guy Harris via tz wrote:
On Feb 24, 2026, at 9:59 PM, Paul Eggert via tz <[email protected]> wrote:
On 2026-02-24 15:37, Samuel Wat wrote:
As for the logistics of where Makivvik is at with making it officially with
TZDB, that's something I can't speak to.
TZDB doesn't have official status in that sense.
Yes. Governments are *not* obliged by any international treaty or other such
binding document to get the TZDB to sign off on time changes.
It would be helpful if governments were to notify us of time zone changes as
soon as they're officially decreed or signed into law - and preferably as much
before they take effect as possible - so that the TZDB project can prepare and
publish updates as soon as possible, so that all of the TZDB's downstream users
can send out updates.
As the "Coordination with governments" section of the main page -
https://data.iana.org/time-zones/tz-link.html#coordinating - says:
As discussed in “How Time Zones Are Coordinated”, the time zone
database relies on collaboration among governments, the time zone database
volunteer community, and data distributors downstream.
If your government plans to change its time zone boundaries or daylight saving
rules, please send email as described in "Changes to the tz database". Do this
well in advance, as this will lessen confusion and will coordinate updates to many cell
phones, computers, and other devices around the world. In your email, please cite the
legislation or regulation that specifies the change, so that it can be checked for
details such as the exact times when clock transitions occur. It is OK if a rule change
is planned to affect clocks far into the future, as a long-planned change can easily be
reverted or otherwise altered with a year’s notice before the change would have affected
clocks.
There is no fixed schedule for tzdb releases. However, typically a
release occurs every few months. Many downstream timezone data distributors
wait for a tzdb release before they produce an update to time zone behavior in
consumer devices and software products. After a release, various parties must
integrate, test, and roll out an update before end users see changes. These
updates can be expensive, for both the quality assurance process and the
overall cost of shipping and installing updates to each device’s copy of tzdb.
Updates may be batched with other updates and may take substantial time to
reach end users after a release. Older devices may no longer be supported and
thus may never be updated, which means they will continue to use out-of-date
rules.
For these reasons any rule change should be promulgated at least a year
before it affects how clocks operate; otherwise, there is a good chance that
many clocks will be wrong due to delays in propagating updates, and that
residents will be confused or even actively resist the change. The shorter the
notice, the more likely clock problems will arise; see “On the Timing of Time
Zone Changes” for examples.
("How Time Zones Are Coordinated" is at
https://www.icann.org/en/blogs/details/how-time-zones-are-coordinated-13-03-2023-en.
"On the Timing of Time Zone Changes" is at
https://codeofmatt.com/on-the-timing-of-time-zone-changes/.)
So "making it officially with TZDB" really means "helping the TZDB project release
updated an updated version of the TZDB containing the change, by notifying them as soon as the
change is official". Doing so is not an official process, it's just a helpful step.
(There are probably other bodies for whom those notifications would be useful.)
Bodies such as ICAO, to which governments belong, may mandate airlines
(including charter carriers which are often not IATA members) follow IATA
standards such as for flight schedule planning and notification.
So the governments' political changes to time keeping laws must be notified to
airlines, and schedule changes notified to IATA for updating SSIM Appendix F
UTC-Local Time Comparisons and ISO Two letter Country Codes (ISO country code,
time Zone, Standard variation to UTC, Daylight Saving Time information) with
adequate notice, or the airlines may be fined millions for inadequate notice!
Of course, the software and information channels used by the airlines and travel
industry may not benefit from their knowledge of government time keeping changes.
So governments and airlines should be encouraged to copy this list on any
changes they are even thinking of making to time keeping.
Unless changes are propagated to this list, and to major software packagers and
distributors as well as major proprietary software vendors, who also subscribe
to this list, with adeqaute notice (at least *MONTHS*), applications and systems
*WILL NOT* be updated in time to be able to handle any time changes politicians
decide on, effectively disregarding any political time changes, until they can
be propagated to the applications and systems used by the governments,
industries, business travellers, and tourists affected by the changes.
See previous discussions on this list and popular media about zero notice time
changes made by Turkey, Egypt, and smaller territories causing cascading
disruptions to travel and economic impacts caused by governments and airlines
using different schedule times from companies and tourists trying to ship goods
and move bodies, and service providers trying to cope with goods not available
and people not appearing when expected!
Not to mention everything else being dropped, skipped, or ignored, rather than
useful work being done on applications and systems needing emergency last second
updates, overtime for testing, and network traffic from everywhere to
everywhere, to ship updates to apply fixes to every affected application,
system, and phone in the world with the wrong time, even if most of those
applications, systems, and phones will never use that time, as all of that
depends only on who communicates with those territories!
Of course, if you are a small territory, you may find major application and
system vendors schedule your timekeeping changes for their regular update next
year, and advise users to change the times on their systems if the really want
to see that time correctly!
--
Take care. Thanks, Brian Inglis Calgary, Alberta, Canada
La perfection est atteinte Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add
mais lorsqu'il n'y a plus rien à retrancher but when there is no more to cut
-- Antoine de Saint-Exupéry
