Jobs that are delayed contain a delay_until field that in new schemas is required to have a date-time format, however it's emitted in internal Mediawiki date format and fails validation. I think it's a good idea to make a schema validate the date-time format, so the following needs to be done:
For transition we need:
- Verify old schema will accept date-time
- Make change-prop support both formats
- Switch MediaWiki to emitting proper date-time format
- After switch to eventgate, remove fallback to old format from ChangeProp