Today brings a sixth title update for Call of Duty: Modern Warfare 3, bringing a host of new fixes and balancing tweaks to the game's competitive multiplayer mode. One fix you'll immediately notice is that Clan Tags will no longer display button icons in place of text; the rest of the fixes happen under the hood.
According to the patch notes, gamers can expect: less lag, a fix for the melee jump glitch, improved host migration logic (YAY!) and no more stat loss when you lose connection from the server.
The update history on the Call of Duty website also runs through some recent HotFix updates (ie game changes that can be made outside of a downloadable Title Update) that were made to vanquish some glitches and rebalance some of the game's weapons. A variety of map exploits have been addressed, as have the No Recoil glitch and Infinite Laptop Killstreak glitch. If you don't know what those are, great! You shouldn't be using them anyway. We also hopefully shouldn't be seeing any more of those hacked bullet-time or high speed lobbies.
On the balancing side, the stopping power for the FMG9 (single or Akimbo) and Type 95 has been cut down a bit. There's also a fix for some issue involving the ACR with a Red Dot Sight and Shotgun attachments equipped, as well as a "fire rate normalization" for assault rifles with undermounts. Head on over to the Call of Duty forums for the full rundown.
Source: Call of Duty website