Matthias Leisi <matthias@leisi.net> writes:
>> This [HINT] says that YOU are supposed to run the ALTER EXTENSION command:
> I did run that, but it seemed to have no effect. How should the update work, what should it do?
What this suggests is that you have a repmgr executable (.so file)
that is newer than the extension's SQL files
(.../share/extension/repmgr.control etc).
You need to straighten out that version mismatch.
regards, tom lane