I tried to install slimserver on my linuxmce server, but wasn't allowed to because of unmet dependencies for libnet-dns-perl, which required the security-updated version of perl (5.8.8-7ubuntu0.1) for feisty, rather than the release version (5.8.8-7build1). I had only the default repositories enabled in apt's sources.list (i.e. local deb-cache, feisty's release, security and updates, and linuxmce's repositories, neither of which seems to be available).
The only way I could get it to install the security updates for ubuntu was to comment out the local deb-cache folder in apt's sources.list. An apt-get update and upgrade then installed a whole host of updates (security and other) including the necessary version of perl. I could then install slimserver. Re-enabling the deb-cache repository then allowed me to install the slimserver-plugin for linuxmce and seemed also to downgrade slimserver from 6.3 to 6.2.2.
Is it safe to install the ubuntu updates like I have done, or will this break linuxmce? If the latter, how does one ensure that the linuxmce server is secure, and reconcile dependencies like this?