@arh@toots.alirezahayati.com

disclaimer:
i haven't used ruby in a while, don't know mastodon and hate debugging ruby. i don't guarantee that this will not break your installation. it likely will :P

vague idea:
maybe the .so file in the error log links against something which got updated on your system and is broken by that.

so.. you could try to reinstall the dependencies (or just the msgpack one), but i don't know how thats done on your install.