For example, I will upgrade Ubuntu Server 20.04 to version 22.04.
Switch to the root user:
sudo -i
Let’s see the current version:
lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04.5 LTS
Release: 20.04
Codename: focal
Update the installed packages and reboot the system:
apt update
apt upgrade
reboot
Remove unused packages:
apt autoremove
Now you can start updating your Ubuntu version:
do-release-upgrade
If the current system has third-party repositories configured that are not compatible with the new version of Ubuntu, then they will be automatically disabled, for example, I had the Zabbix repository disabled, which I then reinstalled but under the new version of Ubuntu.
When asked whether to restart services, I answered “Yes”.
On the server I was upgrading, I had Asterisk, nginx, php and many other services installed.
We agree with the proposal to remove obsolete packages.
Accept the reboot request at the end of the update process.
Done, after rebooting, let’s see the Ubuntu version again:
lsb_release -a
See also my articles:
How to disable auto-update on Ubuntu 18
How to disable “New release available” email notifications on Ubuntu
Updating Ubuntu 14.04 to 16.04