"X Server 1.6 introduces the server bits for Direct
Rendering Infrastructure 2 (the 3D bits can already be found in
Mesa and the Intel driver), X Input 1.5 with device properties,
Predictable Pointer Acceleration, and RandR 1.3. Beyond those key
features, there are also a number of bug-fixes, EXA improvements,
and various other improvements.
"What this release doesn't have, however, is X Input 2 or
Multi-Pointer X even though MPX had entered the master X Server
tree nearly a year ago. A draft of the X Input 2.0 protocol
specification is available. These input features are being held off
until X Server 1.7 with X.Org 7.5."