XFree86 4.0 is the first full release of the new XFree86 4 series. The road to XFree86 4 began in mid 1997, with serious work starting in early 1998. The first pre-4.0 snapshot was released in mid 1999, and 4.0 was released in early 2000. A lot has been completed in that time, and even more has been started since the "4.0" design was drafted. The result is that this release contains a lot of new features, some new drivers, and some significant performance improvements. This release contains components in various stages of development, ranging from stable and well tested to new and not-so-well tested. One the other side, there are drivers from the 3.3.x series that have not yet been ported to XFree86 4. Most of these are for old hardware. To find more information about which hardware is supported, see the Driver Status document.
XFree86 4 uses a very modular design. We had hoped to finalise and fully document the driver module API/ABI in time for the 4.0 release, but instead we are planning to have this done for a subsequent release. We will try where possible to retain backward compatibility with the module interfaces in 4.0 in future releases, but we can't make guarantees about that until the interfaces have been fully documented.
Information on this release's features and their status can be found in the Release Notes.
Information about obtaining and installing binary distributions of this release can be found in the Installation Document.
Copyright and Licensing information for this release can be found in the License Document.