The recent patch from 11-04-2013 includes a following changes:

General:
- Fixed problem with changing in-game mouse sensitivity

Single Player
- Fixed the Memory allocation Crash at the beginning of Siberian Strike DLC which was occurring on lower end machines
- Fixed the issue with disappearing HUD after the bullet cameras on Siberian Strike DLC

Multiplayer:
- Improved stability of the leaderboards system
- Improved functionality of matchmaking mechanism
- Fixed the issue with Client not being able to rejoin LAN session
- Fixed scoreboard issue on the LAN Deathmatch
- Fixed stamina. breath and scope's oscillation malfunction
- Users kicked from the session will not be able to rejoin it
- Server browser will now show all servers from the entire world