Another update which includes World War I has been released: Darkest Hour.
As well as two official updated version/add-ons: Arsenal of Democracy, and Iron Cross.
Has two expansions: Doomsday and Armageddon.
The games allow players to take the role of virtually any country on Earth as of the time at the beginning of the games' various scenarios. A series of World War II Turn-Based Strategy / Real-Time Strategy and management Simulation Games by Paradox Interactive.