Well, they haven't mentioned a patch as far as I'm aware.
On the other hand, judging by twitter start/end times it looks like maintenances without updates have recently usually been less than an hour, and ones with updates around 3-5 hours. As it's 5 hours already, it makes a patch more likely.
5 hour downtime with a 3mb download they changed something be nice if they posted changes before finishing. but normal industry standards apparently dont apply at zenimax they are too elite.