You'll be prompted to download the update upon booting up your game today. It also addresses ghost camera issues and allows players to prime a revive for a DBNO (down but not out) teammate by holding in the Y button before they approach. It's basically the same thing as holding in the X button before approaching a weapon pickup.
Random Quickmatch playlist map order is another addition, as is non-Versus mode weapon swaps in Horde mode. Now, players will find the default weapons on each map that were available when the game initially shipped, as opposed to the current weapon assignments found in online versus multiplayer matches.
[Thanks, Steve D.]