I thought I’d update this VPS from Ubuntu 20.04.5 LTS to Ubuntu 22.04.1 LTS. I ran
do-release-upgrade which gave all the appropriate warnings and stuff, and proceeded to upgrade. This VPS is hosted on Linode, so there’s a local Ubuntu mirror — the download is blindingly fast.
do-release-upgrade process appears to run in a Unix screen window. Unfortunately, that interacted poorly with the terminal I was using, so any time I moved my mouse, it spewed control characters as input. That was bad when it was prompting … something? … probably about my nonstandard sshd configuration.
Anyway, Linode provides a web-based console access, so I was eventually able to fix the broken sshd, PHP, and Apache configurations. Only about two hours of downtime. Not bad for New Year’s Day.