[tz] Recommendations to governments about time zone update notice period and format

Brian Inglis Brian.Inglis at Shaw.ca
Mon Mar 6 21:26:29 UTC 2023

On 2023-03-06 04:41, Neil Fuller via tz wrote:
> The latest short-notice time zone change from Egypt, so soon after the 
> Mexico changes, made me wonder...
> Would it be useful to have a canonical thread or set of links in the TZDB docs 
> to point to for user-facing "Why hasn't my device updated?" or government-facing 
> "Why didn't our legislation change reach citizen's devices in time?" -type 
> questions?
> For example, here are recommendations/policy I know of for a couple of 
> widely-used operating systems / platforms:
> Android: 
> https://source.android.com/docs/core/connect/time/time-zone-policy-recommendations#recommendations <https://source.android.com/docs/core/connect/time/time-zone-policy-recommendations#recommendations> (this is relatively new)
> Windows: 
> https://learn.microsoft.com/en-us/troubleshoot/windows-client/system-management-components/daylight-saving-time-help-support <https://learn.microsoft.com/en-us/troubleshoot/windows-client/system-management-components/daylight-saving-time-help-support>
> Maybe these could be collated and extended for other consumers of TZDB.
> -------
> I vaguely remembered there being something in the TZDB docs that says 
> something along these lines [*] but I couldn't find it and might be getting 
> confused with threads on the mailing list.

Refs in ml and tz-link.html [2016 blog post URL changed but still works] to:




which was followed up in July 2016 with:


while he was still working for MS IIRC.

> I don't honestly expect having it written down to make a lot of difference, but 
> the regular lack of notice and confusion about what /exactly/ governments have 
> changed makes me think there /could/ be a set of recommendations. Then, 
> governments that /want/ to do the right thing could then know what to provide / 
> expect and plan accordingly, and ones that don't try can be easily informed why 
> things didn't work out like they may have expected.

> [*] e.g. maybe something like "Many downstream users of the TZDB wait for an 
> official TZDB release before they will produce an update to time zone behavior 
> in consumer devices and software products. After TZDB has been updated, various 
> parties have to perform their own integration, testing, and rollout of an update 
> before users will see changes. These updates can be expensive, e.g. for the QA 
> process itself and the network costs for updates to each TZDB copy. Updates may 
> be batched with other updates and take substantial time to reach users after the 
> TZDB release. Updates will require that affected products have a suitable update 
> mechanism in place and are still supported."
As governments and/or official airlines also have to update IATA so scheduled 
flight times in the SSIM are correct, we should push for this mailing list to be 
copied on those official distribution lists, so we do not rely on locals 
submitting links to news articles which may lack information that government 
laws, decrees, or regulations /may/ include.

There have been suggestions for FAQs addressing various stakeholders: 
governments, contributors, libc/utility maintainers, package maintainers, 
distros, vendors, end users.
Could we have a FAQ that at least linked to the relevant posts for each.

Perhaps those responsible in vendors, and employees contributing to distros, 
could get together and colloborate off-list to create and post here suitable 
docs, at least containing links, or preferably (links to) articles, like the 
above, the how to, etc. that could be freely distributed, published, and 

Links to these targeted FAQs could then be quoted in replies to government 
officials, etc.

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 retirer     but when there is no more to cut
                                 -- Antoine de Saint-Exupéry

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