On 5th of October 2020, Peter Eisentraut committed patch:
Support for OUT parameters in procedures Unlike for functions, OUT parameters for procedures are part of the signature. Therefore, they have to be listed in pg_proc.proargtypes as well as mentioned in ALTER PROCEDURE and DROP PROCEDURE. Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com> Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/2b8490fe-51af-e671-c504-47359dc453c5@2ndquadrant.com
Continue reading Waiting for PostgreSQL 14 – Support for OUT parameters in procedures