This web page should correct the idea that "upgrades are more risky than staying with existing versions". Is there more we can do? Should we have a more consistent response for such reporters?
It could be helpful to remove this sentence:
"Upgrading to a minor release does not normally require a dump and restore"
While technically true, "not normally" is quite the understatement, as the true answer is "never" or at least "not in the last few decades". I have a hard time even imagining a scenario that would require a minor revision to do a dump and restore - surely, that in itself would warrant a major release?
It would be a crazy idea to report something in the logs if a major version is run after a certain date, since we know the date when major versions will become unsupported.
Could indeed be useful to spit something out at startup. Heck, even minor versions are fairly regular now. Sure would be nice to be able to point a client at the database and say "See? Even Postgres itself thinks you should upgrade from 11.3!!" (totally made up example, not at all related to an actual production system /sarcasm)