Beyond what is planned for X Server 1.6, X Server 1.7 will be the release due as part of X.Org 7.5. The feature freeze for X Server 1.7 is planned for the 21st of January 2009 and the 31st of February will mark the code freeze for this cycle with an X Server 188.8.131.521 / X.Org 7.5 Beta 1 release. A second beta and release candidate are both planned for a March release. Then if all goes according to plan, X.Org 7.5 / X Server 1.7 will be released on April 1, 2008. However, Daniel Stone notes in his mailing list message:
1st April 2009: Release 7.5, makes good April Fool's story. If not, Phoronix gets to run '7.5 released ... nah, X.Org didn't release on time again! April Fool's! Ha!'. Either way, everyone's a winner.