RMAN Compatibility at 8.1.7.4

 I created the Rman user & tablespace and then took the following actions to create the catalogue and set compatibility:-

RMAN>create catalog tablespace rman_data;
RMAN-06431: recovery catalog created

RMAN> configure compatible = 8.1.7;

RMAN-03022: compiling command: configure
RMAN-06456: command not supported

RMAN> upgrade catalog;
RMAN-06435: recovery catalog owner is RMAN
RMAN-06442: enter UPGRADE CATALOG command again to confirm catal

RMAN> upgrade catalog;

RMAN-06408: recovery catalog upgraded to version 08.01.06
RMAN-06452: DBMS_RCVMAN package upgraded to version 08.01.07
RMAN-06452: DBMS_RCVCAT package upgraded to version 08.01.07

When I checked on compatibility it showed the following:-

SQL> SELECT value FROM config WHERE name='compatible';