Alright, so as seen in the CTE, this update adds a decent bit.
Fixes the netcode some more, from what I've heard, but that's not why this deserves a post.
The game gets taken down for an hour tomorrow, starting at 5am (PDT)..
The main thing about this patch is that it adds a new mode, which is Gun Master, from BF3's Close Quarters DLC.
It also adds 5 new weapons: The AN-94, Groza-1, Groza-4, L86A2, and the Mare's Leg.
Mare's leg looks particularly interesting as it's a sawn-off lever action rifle, that is also a secondary weapon.