pg_upgrade fails if privileges have been granted on pg_start_backup()/pg_stop_backup() in the old cluster

Hi,

In version 15 the functions pg_start_backup()/pg_stop_backup() have been renamed to pg_backup_start()/pg_backup_stop().

If privileges on these functions have been granted in the old cluster the pg_upgrade fails.
Our barman user has been granted execute priviliges on these function in PostgreSQL 14 and to avoid the pg_upgrade to fail we had to revoke these privileges in the old cluster before running the pg_upgrade.
No warning/notification is given about this when running pg_upgrade --check.
I don´t know if this is a bug or not but it is really inconvenient to have the pg_upgrade fail/crash (child process exited abnormally: status 256) due to it being unable to grant execute on these no longer existing functions.
It would have been good if a notification about this could have been shown when running the pg_upgrade with the --check option before performing the actual upgrade.

Best regards,
Helena Zetterström