[paulryanrogers]

Good questions. As logical replication matures it may someday be possible to replicate among versions.

[skunkworker]

Logical replication would be nice, but at the moment it's far too slow to replicate for heavy day-to-day use, other than doing a pg upgrade between primaries and replicas.

[sharadov]

I've replicated across different PG versions, there is an extension called mimeo, which is fantastic for logical replication https://pgxn.org/dist/mimeo/1.5.1/doc/howto_mimeo.html