Page "X Window System" Paragraph 127

The Open Group released X11R6. 4 in early 1998.

Controversially, X11R6. 4 departed from the traditional liberal licensing terms, as the Open Group sought to assure funding for the development of X.

The new terms would have prevented its adoption by many projects ( such as XFree86 ) and even by some commercial vendors.

After XFree86 seemed poised to fork, the Open Group relicensed X11R6. 4 under the traditional license in September 1998.

The Open Group's last release came as X11R6. 4 patch 3.