OpenXcom requires a vanilla version of the original UFO: Enemy Unknown / X-COM: UFO Defense (any edition) with the latest patch. It is not compatible with other games in the X-COM series. If you don’t own a copy, you can buy it from one of these retailers.
Do not use modded versions of X-COM, as they may be incompatible with OpenXcom.
Check the Installation documentation for more details.
These builds are automatically generated from the codebase, so they have the latest fixes and updates as well as the latest bugs. Use these if you wanna live on the bleeding edge or to check if a bug is obsolete. Do not install these on top of 1.0!
Maintained by SupSuper
The EXE version has an installer while the ZIP version is standalone. For more details see the FAQ. Latest version is at the top and includes all previous versions:
Mac OS X
Maintained by grrussel
Check this website for more details.
Ubuntu / Mint
Maintained by Krzysztof “Knapsu” Knapik
Available on a dedicated PPA repository. Please do the following in a terminal:
# sudo add-apt-repository ppa:knapsu/openxcom-beta
# sudo apt-get update
# sudo apt-get install openxcom