clean install: you make a backup, nuke the computer, install a fresh upgraded copy of the distro you want from a live usb, copy your data again to the computer.
upgrade: you wait ‘till the distro’ developers release an upgrade you can directly install from your soon to be old distro, you use a command like sudo do-release-upgrade
and why do you upgrade like that?
Clean install on a new computer. Then upgrades until the computer gets retired. Debian at home, Ubuntu server at work.
I like playing with distros and other OSes in VMs, if the thing doesn’t have a well defined upgrade procedure it gets ditched pretty soon.
Try out immutable distros like NixOS: that is stunning in upgrading.
'73
I tried once. Could not figure it out. I’ll leave that to the young people.