According to Treyarch, the upcoming v1.4 patch will feature the Kneedeep, Nightfire, Station maps, will add more weapons and electroshock defenses to the Nazi Zombies map and will toy a bit with the mods.

The full list of features includes as follows:

– Mods: IWD’s can be placed in the usermaps folder.
– Mods: Hold Breath / Sprint functions as intended.
– Mods: MissingAssets.csv is generated when maps are run with developer set to 1.
– Auto balancing improvements. Players are no longer auto balanced while completing objectives.
– Improved spawning logic. 
– Fixed lag caused by shooting at tanks.
– All rifle grenades fired during the first 15 seconds of Search & Destroy will be duds.
– Players who equip a Bouncing Betty and melee teammates in Hardcore game modes are now credited with a team kill penalty.
– Players are now deducted 200 points for team killing the bomb planter/defuser in Hardcore Search & Destroy.
– Martyrdom no longer causes direct impact deaths in Hardcore modes.
– “Bayonet jumping” has been disabled.