§2024-12-07

sudo apt update
sudo apt upgrade
sudo apt dist-upgrade
sudo apt autoremove

sudo reboot now

sudo apt install update-manager-core
sudo do-release-upgrade

$ sudo do-release-upgrade
Checking for a new Ubuntu release
In /etc/update-manager/release-upgrades Prompt 
is set to never so upgrading is not possible.

--> change Prompt=never to Prompt=normal