> On Jan 11, 2024, at 8:29 PM, Andrew Wang <andrew(dot)wang(dot)2009(at)gmail(dot)com> wrote:
>
> Thanks, now 3 versions, 14, 15, and 16 are running as shown below. I did pg_upgrade as detailed below, but it asked me to shutdown postmaster, should which postmaster be down and how?
Both old and new, pg_upgrade will start the ones it needs when it needs them. Strongly suggest you review the documentation, where this is clearly stated: https://www.postgresql.org/docs/current/pgupgrade.html