As of the release of version 4.0.2 in December 2000, XFree86 has three
release branches. The main development stream is on the trunk of the
CVS repository. That is where all new development work is done. A
stable bugfix branch for the 4.0.2 release was created at the time of its
release, and that branch is called "xf-4_0_2-branch".
Fixes for bugs found in the 4.0.2 release will be added to this branch
(as well as the trunk). Similar stable branches will be created after
each full release.
Finally, there is the 3.3.x legacy branch, which is called
"xf-3_3-branch". While this branch is not actively being
maintained, it does include some important post-3.3.6 bug fixes and
security updates. Security updates in particular are usually back-ported
to this branch.
XFree86 is planning to make full releases from the main development stream approximately every six months, in late May and November of each year. The feature freezes for these releases will be 1 April and 1 October respectively. These are target dates, not a binding commitment. How effectively these dates can be met will depend to a large degree on the resource available to XFree86. Full releases consist of full source code tarballs, plus full binary distributions for a range of supported platforms. Update/bugfix releases will be made on an as-required basis, depending also on the availability of resources. Update/bugfix releases will not be full releases, and will consist of source code patches, plus binary updates to be layered on top of the previous full release.
The next full release will be version 4.1.0, scheduled for late May 2001. The next update release will be 4.0.3. There is no specific schedule for that, but it is expected to be available some time in February 2001. The next release on the legacy branch will be 3.3.7. There is currently no schedule for that release. The 3.3.7 release is likely to be the final release on that branch.
Aside from actual releases, snapshots of the active release branches are tagged in the CVS repository from time to time. Each such snapshot has an identifiable version number.