They listed out which titles would be redeemable on Steam, but it only looks to be the most recent Scourge of War: Waterloo, and its associated expansions.
“The games will no longer be available for purchase,” they write, “and we will consequently stop all support and assistance.” Yep, you read it right: starting September 1st, all Scourge of War games will be removed from digital stores, according to a news post on the Matrix Games site.