Dear Maintainer,

What led up to the situation?

I am using Debian 12 (Bookworm/oldstable) with tzdata 2026b-0+deb12u1.
The IANA tzdata 2026c release introduced a change making Morocco
UTC+0 year-round from 2026-09-20. Debian already provides tzdata 2026c
for newer releases, but Bookworm still provides 2026b.

What exactly did you do?

I configured the system timezone as Africa/Casablanca and checked it
after 2026-09-20 using:

timedatectl

What was the outcome?

The system reports:

Time zone: Africa/Casablanca (+01, +0100)

because the Bookworm tzdata package does not contain the new Moroccan
timezone rule.

What outcome did you expect instead?

I expected Africa/Casablanca to report UTC+0 after 2026-09-20, in accordance
with Morocco's current civil-time rules and the corresponding IANA tzdata
2026c rule.

Could tzdata 2026c (or the corresponding timezone correction) be made
available for Debian 12 Bookworm/oldstable?