I have a strange requirement to downgrade from pgsql 17 to pgsql 12. This is because we found in production certain incompatibilities between both versions for our database. It should have been caught in testing but was not.
Agree with others that snap downgrade is not necessarily a good choice here. Either way, if I were in your shoes, I'd be loading a plain text dump, maybe with some light massaging to strip out some compatibility issues.
Can you let us know what the hang up is? Version upgrades these days are usually pretty painless except for some performance issues, unless you have some unusual situations, for example, exotic extensions.
