There were changes made to how group discussion forums are handled internally. IIRC there are a couple of things you need to do.
First thing to understand is that the addon no longer creates real nodes for group discussion forums. Old existing threads and group discussion forums should basically still work the same, but new group discussion threads will all be technically created and internally assigned (as far as XenForo itself is concerned) to the "Archive" node you have set for group discussion forums in the addon's options, and no new real nodes will be created. Instead the addon will maintain pseudo-nodes for group discussion forums that it tracks internally. It does handle permissions to view different threads based on group membership and all that just fine as far as I can tell, and you'd otherwise probably never realize it's no longer creating and using real nodes.
And it looks the same on the frontend... mostly. Slightly different, slightly worse than before. As per my thread here:
These are apart from the other issues with upgrading from an older version of the addon and needing to switch existing forum nodes over to the new node type, or primarily setting up a good individual node as the Archive node where all the new group discussion posts are now actually stored instead of separately created real nodes. Interesting approach, I suppose it cuts down on the potential bloat of loads of real forum nodes added by groups.
Anyway, on to the issues I've noticed.
1. Stickied threads in group discussion forums are not shown properly stickied to the top of the thread...
So here's the thing you probably need to do. Make sure you have an appropriate node available which is set to the new "Group discussions" node type that is now a new thing, and have that node set to not display in the node list. Then choose that node as the "Archive" node in the group discussion options for this addon. It will then be used to store all new threads.
And it should basically just work from there on, from what I recall of making those changes a while back.
Note that if someone knows how to get to that new "Archive" node (through it being shown in the forum list or by a tweaked URL) they can indeed view the node, but only threads associated to groups they have appropriate access to will be shown in there.
All this threw me for a loop a bit at first, but digging at it I found no actual security flaws in how it works, so...
