KDE 4.3.1 has been released.

Users of our latest development release, Karmic, can upgrade to the latest packages.

Users of our stable 9.04 release can install it from the Kubuntu Backports PPA.

deb http://ppa.launchpad.net/kubuntu-ppa/backports/ubuntu jaunty main

It is strongly recommended that you verify the integrity of these packages by installing the archive's GPG key. You may do this by saving the PUBLIC KEY BLOCK available from this page to a file and importing it from the authentication tab in KPackageKit's software sources window.

Then refresh and do a full upgrade.