Mattermost Omnibus and Postgres major-version upgrades?

We’ve a Mattermost Omnibus install that has largely been running in a state of benign neglect since install a few years ago.
It’s on Ubuntu 22.04, and is configured to autoupdate daily when new versions are available. This has worked without incident until today when it updated to MM v8 and failed due to Postgres version requirements.

On inspection, though various new Postgres versions have been installed over time, and all are currently running on that box, there wasn’t any automated migration between new versions as they came available, and all our data was still living in Postgres 10.
This was fine until it fell off the end of “supported versions” treadmill, and the system then fell over.

I’ve manually migrated the data to the nearest supported version (12, on this system) and got things back up and running with a view to fixing things properly in the longer term, but wanted to know if there’s something that I’m missing?

Should Omnibus be migrating between PG major versions when they get installed? Is there a procedure I’ve missed somewhere, or is this a gap in the Omnibus system?

Many thanks.