In April 2013, ' was released on the Steam digital distribution platform for Windows operating systems. The "HD Edition" includes both the original game and the expansion "The Conquerors", as well as updated graphics for high-resolution displays. Originally a fan-made modpack made for "The Conquerors", "Age of Empires II: The Forgotten" was an unofficial expansion that added a new campaign, playable civilizations, maps, and quality of service updates. The Forgotten was later developed into an official expansion with SkyBox Labs and Forgotten Studios, and in November 2013 "The Forgotten HD" was released by Microsoft exclusively for the "HD Edition" on Steam. A third expansion named "The African Kingdoms" was released by Microsoft in November 2015, also exclusively for the "HD Edition". A fourth expansion entitled "Rise of the Rajas" was released on 19 December 2016. On August 21, 2017, Microsoft announced '.