Well before you abandon the idea you should make sure you did not miss any packages in the upgrade dpkg -l | grep 3.1.[345] should get a list of them if you have. If you still want to downgrade then you should use dpkg -l | grep 3.2.0 get a list of the installed packages for the cvs then put a # character to comment out for it the line in the sources.list and then dselect upgrade and then apt-get - s install all_kde_packages_from_list_here remove the -s from the line if the output looks good to actually install. You may also want to try apt-get -s -t testing dist-upgrade and see if it will downgrade the packages to testing (again remove the -s) with that instead of having to type in all those package names.