Just commited a rather large refactoring of the forum module - http://open.silverstripe.com/changeset/98901. This work covers the
major changes required for a couple of tickets (#4944 #4024).
The major changes are:
* Posts now have a parent 'Thread' object rather than pointing to the head post. This has the benefit of tidying up the datamodel and removing some of the thread data (like views) from individual posts and into a much nicer structure.
* Forum no longer uses its strange CheckForumPermissions() function and instead follows the SilverStripe conventional canView(), canEdit(), canCreate() etc etc to handle permissions within the forum which makes the permissions system much more portable.
Because of the changes required in the templates for both of these changes your customized forum themes will not work with trunk currently. If you've been running on forum trunk (for getting it to work on 2.4) then you can switch safely to branches/0.3 for forum.
I've got a couple bugfixes for branches/0.3 then we'll release an official 0.3 release for 2.4. You can download branches/0.3 from http://open.silverstripe.com/changeset/latest/modules/forum/branches/...
If you have any other projects just starting out or still using the default forum templates then I would love for you to download trunk rather than 0.3 and have a play around with these changes. There is a data migration script for posts, threads and subscriptions which you can run so your data can be upgraded without too much hassle. Its just the templates which are a pain!. Migrating the ssorg forum to the new format took roughly 4mins for the 9000 threads I ran it on so give the migration script a bit of room to run.
The full upgrade notes are available in the forum download in the /docs/ folder. Would love to hear your thoughts / questions / comments.