2009-02-20 (updated 2010-11-14)
Non-free add-ons: (DLC)
* Operation: Anchorage (2009-01-27)
* The Pitt (2009-03-24)
* Broken Steel (2009-05-05)
* Point Lookout (2009-06-23)
* Mothership Zeta (2009-07-29?)

Available only through the Microsoft LIVE service (for both Windows and X360). GOTY edition of the game comes with all five DLCs included.