There was mention that the server would be down for some maintenance. It was down for about a day or longer.
<STRIKE>Ubisoft technicians must have restored the forum from some earlier backup in order to get the forum "up and running".
If they have "incremental backups" to restore thereafter, they have not yet applied those incremental backups.
If the October backup is the only reliable backup that Ubisoft had, then Ubisoft may have needed to fire someone for not properly backing up their server(s).
I am only a 30+ year I.T. professional guessing at what happened.</STRIKE>