The studio is still posting news about it.
Released in Oct 2012.
Its posts are not marked as updates on Steam, so there is no update pattern to show.
The XCOM: Enemy Unknown - Slingshot Pack is Now Available!
Everything Steam has posted for this game, updates and announcements alike.
News1mo agoCozy Up with 2K: The Autumn Sale is Live on Steam! Save Big Through Oct 8.*
News4mo agoTime to Play: The 2K Summer Sale is Officially Live on Steam
News57mo agoXCOM 2: WAR OF THE CHOSEN PLAY FOR FREE
News79mo agoXCOM: Chimera Squad - Available Now on SteamNews79mo agoXCOM: Chimera Squad, all-new story in the XCOM universe, launches April 24
News98mo agoXCOM Retrospective - Legacy Devs Livestream