yesterday I’ve upgraded my notebook to the development version of Kubuntu, there was only 2 problems. The first is that my “sudo update-manager -d” does not work properly, I got a dependency break that I resolved reading the relative Launchpad bug. Another problem was a post upgrade problem, the nvidia driver (ver. 256.44) was not loaded and for resolve it I just added the following lines to my generated (with nvidia-xconfig) xorg.conf
Option "IgnoreABI" "True"
Now everything seems to work well!