That’s great! Indeed there are many “unsupported” installs that work just fine. It’s just that they pose the posibility of many issues that are difficult or impossible to diagnose here. External Postgres is among the easier things to make work. I know that PG15 is “supported”. I’d expect PG16 to work, as generally new Postgres versions are backward compatible, though there was a time that some newer-than-supported postgres had some strange issue (which has since been fixed).