XORG Software and Technology
The X.Org project is focused on creating an open source implementation of the X Window System. The X.Org server (officially the X.Org Foundation Open Source Public Implementation of X11) is the X server in the official implementation of the X Window System. The current release is 1.5.3, which is part of X11R7.4, which was released on September 10th, 2008. The software is open source and thus free software.