So earlier this evening (I guess I started around 23:45) I tried to upgrade the forum to the latest release.
Unfortunately it failed - I think because of the chat room (I'll uninstall that before upgrading again).
I've rolled everything back (from backups taken immediately prior to the change), but I can't be 100% sure that everything is as it was.
Any issues or 'oddness' in the forum just reply to this posting to let me know.
Many thanks.