High level step from upgrading database from 11.2.0.2 to 11.2.0,4 .

Below are simple high level steps  from upgrading database , Using below steps i upgraded 08 Prod database from 11.2.02 to 11.2.0.4 . here my source and target home is Some location .
 
1.- New Oracle home need to be install on server.
2.- run this command in new home  to pre check error
  NEW_ORACLE_HOME/db/rdbms/admin/utlu112i.sql
  
3-check spfile in common location
4-then run this command 
SQL> alter system set cluster_database=false scope=spfile sid='*';
5-Copy pfile in new home
6-export new oracle home :to make sure db home is new home
7- startup upgrade
8-@?/rdbms/admin/catupgrd.sql
9- shutdown immediate
10-startup
11-@?/rdbms/admin/catupgrd.sql
12@?/rdbms/admin/utlrp.sql
13-Change env file new home ~/bin/sid
14-Copy listener and tns new home  , please ignore if  listener is running from GI Home. 
15- copy password file into new HO .
16- now let upgrade new RDBMS Home(from where Oracle running )
srvctl upgrade database -d db_unique_name -o Oracle_home 
 (change above to db_unique_name and Oracle_home)
17- Now lets  make cluster_database=true in parameter file
alter system set cluster_database=true sid='*' scope=spfile; 
18- Change or update new HO in env file and pfile on all rac node.
19 -Using srvctl start your db.
20- check if all component are upgraded to new version.
SELECT comp_name || ' : '||version|| ' : '|| status FROM dba_registry;