X11R7.7 development is development is complete: the final release has been posted at http://www.x.org/releases/X11R7.7/
Update: Many modules have had new releases since the X11R7.7 katamari - see the individual X.Org releases directory for downloads, and the xorg-announce archives for details on included changes. These updates may be included in a future 7.8 katamari release if one is ever assembled.
Security issues have been found in the X11R7.7 software since its release. See the Security Advisories against X11R7.7 for more information and links to fixes.
See also: Summary of new features in X11R7.7, Combined ChangeLog for all X11R7.7 components (1.5 Mb)