When connecting to rman, “PLS-00201: identifier ‘DBMS_BACKUP_RESTORE.SET_CHARSET’ must be declared” error and connection could not be established.
Problematic DBMS_BACKUP_RESTORE package or invalid sys objects or database logon triggers may change the current firmware.
First check the logon triggers. If all the connections have a trigger that changes the current thread, delete it.
If there are invalid objects in the SYS diagram, recompile them to make them valid.
Either open your database with startup upgrade and run the utlrp.sql after catupgrd.sql or run dbmsbkrs.sql and prvtbkrs.plb scripts
SQL> startup upgrade