The release numbering is based on the original MIT X numbering system. X11 refers to the version of the network protocol that the X Window system is based on: Version 11 was first released in 1988 and has been stable for 15 years, with only upward compatible additions to the core X protocol, a record of stability envied in computing. Formal releases of X started with X version 9 from MIT; the first commercial X products were based on X version 10. The MIT X Consortium and its successors, the X Consortium, the Open Group X Project Team, and the X.Org Group released versions X11R3 through X11R6.6, before the founding of the X.Org Foundation.
X11R6.7.0 is based on the merger of the X11R6.6 and XFree86 4.4RC2 codebases, with significant updates, noted below.
There will be future maintenance releases in the X11R6.7.x series. However, efforts are well underway to split the X distribution into its modular components to allow for easier maintenance and independent updates. We expect a transitional period while both X11R6.7 releases are being fielded and the modular release completed and deployed while both will be available as different consumers of X technology have different constraints on deployment. We have not yet decided how the modular X releases will be numbered.
Due to the new XFree86 1.1 license introduced in XFree86 4.4 (final), later additions to XFree86 may not be incorporated into our codebase. We encourage you to submit bug fixes and enhancements to bugzilla.freedesktop.org using the xorg product, and discussions on this server take place on firstname.lastname@example.org .