Battlefield 3's next DLC called Armored Kill is coming out on September but EA decided to give the community a heads up on what to expect in Aftermath, the fourth DLC that's planned for a December release.
Here is a small description given by EA about Aftermath.
Set amongst the shattered districts, streets and surrounding villages of a post-earthquake Tehran Battlefield 3™: Aftermath depicts a continuing struggle for supremacy and survival amongst the devastation.
With operational capacity severely compromised the opposing forces must adapt and engage in vertical and horizontal urban combat amongst the dust and rubble with cracks and fissures in the terrain providing unexpected cover and paths to objectives. Additional support comes in the form of heavily modified troop transports and civilian vehicles specially adapted to deliver deadly force to the enemy.
- Urban warfare on four new maps
- Fight through the dust and rubble, use the earthquake damaged terrain to your tactical advantage
- New heavily modified military and civilian vehicles – ingenuity and firepower combined
- New game mode
- New assignments, achievements and dog tags
No official date has been given. Even Armored Kill has no date still, which is scheduled to be released first.
After Aftermath is released in December, only one DLC remain for Battlefield 3 - Endgame, which is planned for an early 2013 release. Curious to what they mean about using earthquake damaged terrain as your advantage. I have a feeling it's just properly placed rocks that can be triggered to drop on players.