Hi!
- Is that stability now reached?
- Is there some sort of flag-mechanism, that would indicate if the
SPARQL endpoint is stable, being upgraded or had change in state?
It's supposed to be stable now, though there's at least one known bug (not affecting you unless you run the affected query, but if you see NotMaterializedException you probably hit it, it's being worked on and will be fixed soon, ping me if you want boring details).
In general, the upgrade went fine so I didn't send a note but then apparently (of course, as soon as I waited to ensure everything is going fine, which it was, and went to sleep) something gone wrong and I'm still not sure what exactly - I'll continue to research that, but whatever happened doesn't seem to repeat itself so far. In the future, I'll make announcement when I do potentially risky stuff.
We have a number of plans for implementing new functions which would involve full DB reload at least once - which will mean the DB will be temporarily reset to the state of the latest weekly dump (i.e. 2-3 days behind current state of wikidata) and then will re-sync with the current state over the course of a day or so. I'll write about that additionally before we do it, depending on how development is going could be end of this month or somewhere next month.
Thanks,