Each major version of PostgreSQL (in theory) can come with breaking changes in their API and internals. One such breaking change was thenon-optional addition of ALPN to the TLS connection process in PostgreSQL 17. As a result,libpg v17 contains this breaking change, so it isrisky to linkpsql v16 againstlibpg v17.

In fact, The Official PostgreSQL Docker Container since tag 16.4 is linking againstlibpg v17 producingreal problems in production: Once PostgreSQL v16 (!) is proxied (e. g. TLS termination is not performed by PostgreSQL itself but by Traefik, as typical in cloud environments etc.),psql v16 (!) fails to connect due to missing ALPN custom namepostgresql (remember, only v16 is in use here on clientand server, and ALPN support was invented in PostgreSQL v17 but doesnot exist officially in v16.x)!

As such a breaking change iscounter intuitive (and forbidden by SemVer), I kindly ask the PostgreSQL Docker Community to link 16.x againstlibpg v16 instead of v17.

Disclaimer: The source of this information isTom Lane, I just forwarded it.