Marking all / specific forums should work now.
This will differ from senv4 in a couple of ways...
1. Marking a forum will be database driven, instead of cookie driven. So, changing computer locations won't affect what forums you marked as read.
2. Last visit date or whatever will not automatically mark forums and topics as read. I generally perfer this method as opening a session on sen doesn't necessarily mean you will read all the topics on the whole board. Perhaps, maybe you want to sign in to check your messages and not the board... so there should be no reason why the board should mark itself as read.
Edit: Still some errors with this...
I think it's mostly for IE in some certain type of caching...
header('Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0');
header('Pragma: no-cache');
Can't hurt to try.