I don't know how many of you still play this, but new (free) DLC will be available this month. It's offered to everyone in celebration of Killzone's 10th anniversary. All players will receive a remake of one of the most popular Killzone 2 MP maps, Academy.
On top of that, people who own the co-op DLC will get two new maps for free, and anyone who owns the season pass will get a bunch of new customizations such as weapon reticles, skins, etc.