Hello all,

The SRE and MediaWiki Engineering teams have started the process of migrating production MediaWiki workloads at WMF from PHP 8.1 to 8.3 [0], with a small-but-growing fraction of traffic serving on 8.3 since late last week.

This follows a long-running effort to prepare MediaWiki and our production environment for 8.3, and builds on what we learned while migrating from 7.4 to 8.1 earlier this year.

*What is the expected timeline?*

With the migration in its early stages, we anticipate completion within the next 2 - 3 weeks. More details on the migration process and timeline can be found in [1].

The timeline is subject to change if issues related to PHP 8.3 compatibility arise (i.e., requiring a pause or revert to 8.1).

*What if I discover a production issue related to PHP 8.3 compatibility?*

If you discover an issue related to the 8.3 migration, please open a subtask of [2] to report it.

In the event of an urgent or widespread issue that warrants reverting traffic to PHP 8.1 as soon as possible, please escalate to SRE in #wikimedia-sre on IRC.

Feel free to reach out if you have any questions or concerns, either to me directly, on this thread, or via a task on Phabricator.

Many thanks to all who have been involved in moving MediaWiki at WMF forward to PHP 8.3!

Scott French Service Ops SRE

[0] https://phabricator.wikimedia.org/T360995 [1] https://phabricator.wikimedia.org/T405955 [2] https://phabricator.wikimedia.org/T401855