In any case, I don't really understand how Gitlab can get away with saying "you have to keep your gitlab instance updated all the time" - which is not explicitly documented, but it's how you interpret the middle finger gitlab gives you every time you try to update it.
I did a major version update - tried updating from a 13.something to 14.2.1 - surely enough, it told me it couldn't do that, and that I should have updated to 14.0 first. Fine, although it's not like I'm skipping a whole new major version, are you telling me that you don't keep old migrations between minor versions?
And then, to update to 14.2.1 they expect a specific "background migration" to be finished, which is available from 14.0.5 / 14.1, and that even if it says it's finalised it doesn't seem to be actually finalised when you try to update it to 14.2.1.
Guess I'll just have to wait a few more days and see what happens 🤷♂️