Ubuntu notes

As of 2025 Q2 Ubuntu server dist upgrades require a package which is not installed in minimal Ubuntu install processes. To install the automating distribution upgrader (note 1):

 $ sudo apt install ubuntu-release-upgrader-core

To start the distribution upgrade:

 $ sudo apt do-release-upgrade

Notes

(1) https://www.cyberciti.biz/faq/ubuntu-bash-do-release-upgrade-command-not-found/