Step 1. Backup
Step 2
Replace focal with jammy in /etc/apt:
Step 3
apt update
apt upgrade
Step 4
How do I set the default version for PHP CLI installed via APT?
Step 5
Step 6
reboot
Step 7
How did I fix «Synchronizing state of proftpd.service with SysV service script with /lib/systemd/systemd-sysv-install» / «Could not execute systemctl: at /usr/bin/deb-systemd-invoke line 142» after upgrading Ubuntu from 20 to 22?
Step 8
How did I fix «The following packages have been kept back» on apt-get upgrade?