Is anyone using private forums at the moment?

!Friendica Support I’m currently working on the message transport of private forums. Currently this is still done in the old protocol. I want to change it so that it is working in Activitypub so that eventually people from other systems can also participate (like they can do with public forums).

Currently it seems as if this is a breaking change. Means: When I have applied all changes then there will be no backwards compatibility. Means: When the server changed to the new version then all users have to – and vice versa.

So the question is: how widely used are private forums? Is anyone subscribed to such a forum? Is there currently traffic? Thanks!