Event federation limitations

Event created by a profile, and sent to instance followers

Software	Create event	Update event	Delete event	Joining the event
Mobilizon	✅	✅	✅	✅
Mastodon	✅	❌¹	✅	❌²
Friendica	✅	✅	✅	❌³

Now when the event is created on behalf of a group, and activity sent to group followers

Software	Create event	Update event	Delete event	Joining the event
Mobilizon	✅	✅	✅	✅
Mastodon	✅⁵	❌¹	❌⁴	❌²
Friendica	✅⁵	✅⁶	❌⁴	❌³

¹ Mastodon does not support the Update activity (apart from accounts and polls).

² Mastodon does not support joining events (events are considered plain messages).

³ Friendica only does RSVP answers on Events, which is a different vocabulary choice than Mobilizon currently does. See #922 (closed)

⁴ Deleting events on behalf of a group is only supported in Mobilizon for now, as group support - at least how we designed it for now - isn't supported across the fediverse. See #924 (closed)

⁵ The event shows as reshared by the group itself in timelines. Related to above issue.

⁶ Odd that Friendica allows to Update the group event but not Delete it.