I tried upgrading my Postgresql 14 instance on Ubuntu 22.04 to Postgres 16 today, using the info provided here: https://maas.io/docs/how-to-upgrade-from-postgresql-v14-to-v16
Unfortunately this guidance doesn’t work, as after the apt install step, there isn’t actually a Postgresql 16 instance running. The guidance assumes running completely side-by-side, which takes more skill to set up. The guidance that does work is found here: https://www.directedignorance.com/blog/upgrading-postgresql-14-to-16-on-ubuntu
Those steps will properly update Postgresql 14 to 16 in-place without issue.