Just FYI for everyone, I've written a replacement module for the private messaging system that should address the inadequacies of the old system.

They now present themselves similar to topics and handle all of the parsing in the same way, allowing multiple users to be properly invited into a conversation. It isn't perfect, and I'm sure there's probably lurking bugs, but at the moment it seems to be working.

Unfortunately the nature of how old PMs were stored in the database makes it impossible to convert them into the new system without my reading every last message that's currently being stored. Which would obviously cause a serious breach of privacy. So I've hacked the old PM system to handle replies to old messages as the start of a new conversation with the user you're replying to. It will auto-quote the text from their reply in the process, making it easier to transition over.

The old system will no longer process an attempt to post a new PM using it. You can still read the old messages, and delete anything you want to clean up there.

Please let me know if something doesn't look right, other than the crappy formatting of the participants list in a conversation. I'm trying to figure out a nice way to clean that up a bit more but can't come up with the HTML to do it yet. If something should end up crashing the new messaging system I'll get an email about it and will fix it as time permits.