This announcement was significant in that it had taken a year to go from X Server 1.4 / X.Org 7.3 to X Server 1.5 / X.Org 7.4 (and there was six months just for a point release), but Keith would throw X Server 1.6 together in just about three months.
Keith's intentions for X Server 1.6 is strictly a time-based release cycle as there are some features not yet in a released version of the X Server that he would like to have available to Intel's customers. X Server 1.6 is scheduled to introduce Predictable Pointer Acceleration, a revised version of DRI2 that hadn't made it in time for X Server 1.5, RandR 1.3 (the Resize and Rotate extension), and X Input 2 or X Input 1.5 with device properties. If X Input 2 is primed for X Server 1.6, this server release will also arrive with Multi-Pointer X support.
Since XDS we haven't heard any more on the schedule of X Server 1.6, but this afternoon Keith Packard had provided an update on the X.Org mailing list. Keith is hoping to branch X Server 1.6 from git master on November 24 and then create an X Server 1.6 Release Candidate 1. Following that, X Server 1.6 Release Candidate 2 is scheduled to ship on December 8 and a third release candidate on the 23rd of December. Around the time period of X Server 1.6 RC3, efforts will turn from new code development to bug fixing. With the current schedule, X Server 1.6.0 would then be released on the 5th of January.
This is just days after the end of 2008, but shouldn't be bad as long as the release schedule is met and the bug blocker list at least semi-cleared. If the original X.Org 7.5 release schedule remains in tact, the release of that with X Server 1.6 or X Server 1.7 will be occur on the first of April.
When it comes to RandR 1.3 support, just minutes after announcing this release schedule, Keith Packard proposed a series of patches (32 in total) that add projective transform support. Discussed recently have also been new properties for RandR 1.3.