Packages for the release of KDE SC 4.10.3 are available for Kubuntu 13.04, 12.10 and 12.04. You can get them from the Kubuntu Updates PPA for 13.04 and from the Backports PPA for 12.10 and 12.04.
To update, use the Software Repository Guide to add the following repository to your software sources list:
Or, from your konsole:
Thanks to Philip and Rohan for their work on these packages