It's easy but I ran into a problem.
So after that:
sudo sed -i 's/raring/saucy/' /etc/apt/sources.list sudo sed -i 's/olivia/petra/' /etc/apt/sources.list sudo sed -i 's/raring/saucy/' /etc/apt/sources.list.d/official-package-repositories.list sudo sed -i 's/olivia/petra/' /etc/apt/sources.list.d/official-package-repositories.list sudo apt-get update && sudo apt-get dist-upgrade sudo apt-get upgrade
It took a while and after the reboot (used
sudo shutdown -r nowbecause the dialog to restart was no longer readable), I ran into a requester saying "There was an error loading the theme BlackNBlue".
Yes, you guessed it, I installed a theme on Olivia and it didn't survive the upgrade. I couldn't log in, and there was no way to getting to the GUI. So I started an editor and changed the HTML-Theme to "Clouds" at /etc/mdm/mdm.conf (see screenshot).
After another reboot the login-screen appeared and worked as intended.
However, I found the settings and panel-entries for the settings were all doubled. One started the gnome-control center and the other the cinnamon settings. I edited the menu to get rid of the gnome-panels. Uninstalling would have brick some of my installed programs, which might be the reason they are here at all.
So no big deal in the end, and now I'm enjoying a new Mint system, hopefully without the "Dummy Output" sound bug appearing randomly after booting, like Olivia did.