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
from what i can tell (from the work in progress pull request) mastodons group implementation explicitly does not aim for compatibility with lemmy
other than that, i agree on activitypub being crap in terms of making interoperability easy
@ShittyKopper rightly mastodon cannot and should not aim for full compatibility with Lemmy and Piefed.
In fact, Lemmy has some unique features (such as the intentionally limited management of crossposting) that cannot be managed.
However, it would be appropriate and above all ethical, for Mastodon groups to be compatible with Friendica groups, Gup groups and Mbin magazines.
This would allow mastodon users to continue using the Activity pub groups of other platforms, including Lemmy.
I remember in fact that even WordPress (which at the moment, represents the most important novelty of the Fediverse) is perfectly able to publish on the Lemmy communities and on the Friendica groups!
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