KDE 4.x has been criticised for not being user-friendly enough, but the developers are sticking to their original vision of making and beyond a "mainstream" desktop environment.

According to the KDE project, the most notable improvements in this release have been made to Okular, the document viewer, Kopete, the instant messaging client, KMail, KDE's email client, and KHTML which received many bug fixes, optimisations and feature improvements.

KDE 4.2.1 also ships more translations.

At release time pre-compiled packages are available for Mandriva and OpenSUSE, with packages for Ubuntu (and Kubuntu) likely to follow soon.

For a digested summary of the changes made since the 4.2.0 release, see the .