Display the RDBMS Version Number

EXEC DBMS_OUTPUT.PUT_LINE(DBMS_DB_VERSION.VERSION)

Enable All Compilation Warnings

ALTER SESSION SET PLSQL_WARNINGS='ENABLE:ALL'

CREATE OR REPLACE PACKAGE pack11 AUTHID DEFINER AS    
 $IF DBMS_DB_VERSION.VER_LE_11     
 $THEN    
    PROCEDURE proc1;    
 $ELSE    
    PROCEDURE proc1;    
    PRAGMA DEPRECATE(proc1);    
 $END    
    
 PROCEDURE proc3;    
END pack11; 

Display All Compilation Warnings for Unit PACK11

SELECT * FROM USER_ERRORS WHERE NAME = 'PACK11'