I tried to do this during the weekend.
I do not know if I did well, but I changed the word "belenos" to flidas in
the repositories at /etc/apt/sources.list and later I tried:
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
In the second step ("upgrade") the bottom of power dissapeared. After doing
"dist-upgraded" it appeared again but I was not able to shut-down the
computer neither to restart. The desktop environment looked the same, and I
did encounter other errors but now I am not able to recall them here.
For the case of being of some help I will comment here that today I tried to
take from the flidas repositories the package for firejail. But I get an
error of authetication due to a non recognised key. I leave here my error:
W: GPG error: https://mirror.fsf.org flidas InRelease: The following
signatures couldn't be verified because the public key is not available:
NO_PUBKEY B138CA450C05112F
