I can update my Ubuntu to the new LTS version. As you can think, its not a highly important server since I run 13.10 (not a LTS version). Anyway - I actually want to upgrade my server, but would like to be able to revert this upgrade.

I would be able to reinstall Ubuntu 13.10 and overwrite it with my backup. But I want to know if there is a more comfortable way to do this. TBH I guess theres no command as undo-release-upgrade but I thought it would be worth to ask for it.

This is my current daily backup script

tar cvpzf $backup_file --exclude=/proc --exclude=/lost+found --exclude=$backup_file --exclude=/mnt --exclude=/sys --exclude=/media --exclude=/tmp /