Since 9 there's pg_upgrade, personally I never had an issue and it was very fast, so the downtime is in the order of a few minutes, which is ok for my usecase. YMMV.

"pg_upgrade does its best to make sure the old and new clusters are binary-compatible, e.g., by checking for compatible compile-time settings, including 32/64-bit binaries. It is important that any external modules are also binary compatible, though this cannot be checked by pg_upgrade."

This makes me very nervous tho, I've at least two exts (trigrams and gists) maybe they work, maybe not, I just prefer the ease of mind of a old fashioned dump.

Don't take my word for it, but I think those extensions aren't considered "external" as they're part of the PGSQL distribution.

It'd be something like nominatim.so, which is external to PGSQL and (AFAIK) has its own format for certain types of data and indexes.

Ever since there's pg_upgrade available. Since 8.4 or so - https://www.percona.com/blog/2019/04/12/fast-upgrade-of-lega...

Dump and reload is ok if you have a small database or can afford hours of downtime... if not, use pg_upgrade.

It never did.

The difference is that you can use logical replication since 10 to prevent downtime during upgrade.

Which if you were using it a year ago could have been done.