During today's train deployment for 1.37.0-wmf.23,  we discovered a couple of blocking issues which resulted in rolling back to group 0.

Here they are in all of their glory:

1. T291128 Wikimedia\Rdbms\DBQueryError: Error 1146: Table 'arbcom_dewiki.echo_push_subscription' doesn't exist
2. T291124 PHP Notice: Undefined index: format

The first issue is puzzling.  The error was noticed during roll forward but the stack indicates that it's version wmf.21.  Furthermore, as pointed out by subbu, the table should have been created back in 2020:

subbu> https://github.com/wikimedia/mediawiki-extensions-Echo/blob/master/db_patches/echo_push_subscription.sql ... 2020.

There is ongoing discussion in IRC around this so perhaps it's fixed by the time you read this.

The second issue appears to be related to compatibility of serialized objects across versions. See the task for some commentary by Daimona.

If you've got any ideas, we'd love to hear your thoughts. Patches are also welcome.:)

<3

- Your humble train (co-)conductor.