[tz] Palestine winter time

[Paul Eggert]

On 10/18/21 09:08, Sharef Mustafa via tz wrote:
> Thanks for posting this P Chan
> 
> the only formal news source is a post on the facebook page of the
> Palestinian government
> <https://www.facebook.com/PMO.Palestine/posts/4831752950190822> which says:
> 
> " بدء العمل بالتوقيت الشتوي اعتبارًا من منتصف ليلة الخميس/ الجمعة 29/ 10"
> which P Chan exactly translated it to:
> "Palestine winter time will start from midnight 2021-10-29
> (Thursday-Friday)."

Thanks for the heads-up. This announcement is unclear, as it could mean 
that the transition is:

(A) from Thursday 10-28 24:00 to Thursday 10-28 23:00.

And it could also mean that the transition is:

(B) from Friday 10-29 01:00 to Friday 10-29 00:00.

For Palestine's transition to winter time, tzdb currently uses method 
(A) for 2014 and 2019, and method (B) for 2015-2018 and for 2020-2021. 
Do you know which is the correct method for the year 2021? If method (B) 
is correct, tzdb is already OK; if not, we'll need to update tzdb.

Surely it would be better for everyone concerned if Palestine were 
consistent about using method (A) or method (B). I worry that the actual 
transition rule has not been specified clearly and that tzdb has been 
interpreting ambiguously-specified rules somewhat at random.

Thank you for any info you can provide to clear this up.