PostgreSQL 19 changes five server defaults: jit (on to off), max_locks_per_transaction (64 to 128), default_toast_compression (pglz to lz4), log_lock_waits (off to on), and standard_conforming_strings
General availability moved from an original October 29, 2026 target to November 19, 2026, after the release team added a second release candidate on November 12 to absorb a larger-than-usual backlog
pg_upgrade now rejects two cluster states outright: object names containing a carriage return or line feed, and btree_gist indexes on inet or cidr columns, both of which need fixing before migration