KDE SC 4.11 is here and KDE distros have started making it available for their users. Kubuntu users can upgrade to 4.11 by simply adding a PPA.
KDE SC 4.11 packages are available for Kubuntu 12.04 LTS, 13.04 and other development releases.
In order to upgrade add the backport PPA by running this command:
sudo add-apt-repository ppa:kubuntu-ppa/backports
sudo apt-get update
sudo apt-get upgrade
However, if you are running Kubuntu 12.10, you won’t get this PPA as developers said that due to lack of demand (not many people seem to be running 12.10) they are not making the port available for the version, so if you are running 12.10, it’s better to upgrade to 13.04.