X.Org 7.6 Released

XCB did never quite replace Xlib but these days Xlib is built on top of XCB. Also, the XCB code is automatically generated from the X protocol specifications, so at some point it becomes "complete", and only minor bugfixes and additions to the protocol need to be added. It might seem "dead" but in fact there may be nothing important to do.

XCB still has it's sore points, though. For example using OpenGL requires you to use Xlib, because GLX is defined in terms of Xlib (more info: http://xcb.freedesktop.org/opengl/).

I think that the *nix desktop world needs to get a kick and find a new direction. X is really old, Xlib is a horribly designed library and window managers are an afterthought. Perhaps Ubuntu and the new Wayland graphics stack will do it, but it might as well be nothing but vapor. The support of commercial graphics vendors is also required.