X11

In OpenWindows V3, the X11 protocol and XLib (the client library) were maintained with 100% backwards compatibility with OpenWindows V2. Both releases support Revision 4 of the X11 MIT protocol. The OpenWindows V3.3 release does contain a large number of bug fixes, however, that make it more protocol reliant than OpenWindows V2 was. If an application relies on an incompatibility with the protocol, it may no longer work.