This release features security updates, video driver
enhancements, input driver enhancements, IPv6 support, X
Server and extension updates, client and library updates,
I18N and font updates, and OS support updates.
A zlib bug that may have security implications on some platforms has been fixed. MIT-SHM has been updated to not access SHM segments that the client doesn't have sufficient privileges to access. An Xlib problem that made it possible to load (and executure) arbitrary code in privileged clients has been fixed. This release is available only in the form of a patch to version 4.2.0.