"apt-get update" only refreshes the local list of available packages. to upgrade everything, use "apt-get dist-upgrade".
I am no expert but the installation page advises against that:http://wiki.linuxmce.org/index.php/Installing_0810
Note: You should NOT run apt-get dist-upgrade after the initial install, as it can cause several problems, including having different kernel versions on your core and media directors, and the installation of new Kubuntu packages that can break some features!
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