The KDE project has announced the first release candidate of the pending 4.1 release due out at the end of July.

KDE 4.1-RC1 is intended to be used for testing the upcoming KDE 4.1 release and to filter out last-minute bugs, according to the project.

This means KDE 4.1 is frozen for new code contributions unless the updates have been reviewed and are for bug fixes only.

"This way, regressions are kept at a bare minimum," according to the developers.

The release follows KDE 4.1 beta earlier this year.

The KDE 4.1-RC1 source packages can be downloaded from the information page.

Pre-compiled binary packages are also available for the popular Kubuntu and OpenSUSE Linux distributions.

The development in the Subversion /trunk repository has been opened for feature development, which is going into KDE 4.2 to be released in January 2008, but KDE developers are being encouraged to concentrate on bug fixing in the 4.1 branch.

There is only one week until 4.1 will be tagged for release.

A known bug is some users might be experiencing performance problems with NVidia graphics chips and the proprietary drivers.

The problem affects window switching and resizing. The KDE project has alerted NVidia to the problems, but no fixed NVidia driver has been released.

The final KDE 4.1 release is scheduled for July 29.