I missed when it happened, but #guppe is now at the "a.gup.pe" address. Adjust your groups as needed.

For those who don't know, it is a server where you can make groups by just mentioning them in a post. Anybody who subscribes to such a group receives all the posts that have that name tagged. A bit like subscribing to a hashtag, but in the fediverse hashtags don't federate, so that doesn't work; this does.