Warning: we advise lemmy.world administrators to wait to update to 0.19.5 due to an incompatibility with the latest Mastodon releases
As it emerged in this thread, messages from the latest versions of mastodon are not interpreted correctly by the latest Lemmy releases
iirc mastodon was implementing smithereen’s flavor of groups. no idea if they ended up changing course or anything (not following masto dev tok closely) but the way they work is fundamentally different from how Lemmy and compatible groups work
it’s still a pull request on GitHub, however I think Lemmy 1.0 will be released sooner than it will be merged