Follow the steps to upgrade oracle version from 10.2.0.x to 10.2.0.4.
Step1: Download the patch 6810189 from Metalink and extract the file.
$ unzip p6810189_10204_LINUX-x86-64.zip (ex:- for linux 64 bit)
Step2: - Set the ORACLE_HOME and ORACLE_SID and backup the database
$ ORACLE_SID=testdb; export ORACLE_SID
$ ORACLE_HOME=/oracle/v10201; export ORACLE_HOME
Backup the databases using RMAN or command line file level backup, if any
Step 3: Shutdown database and all other processes/services.
Shutdown listener, if running on same version
$ lnsrctl stop
Stop dbconsole, if any
$ emctl stop dbconsole
SQL> SHUTDOWN IMMEDIATE
Step 4:- Backup Oracle home and Inventory.
Oracle recommends that you take a backup of Oracle Inventory and Oracle home.
Step 5: Start the OUI and install the 10.2.0.4
For Unix:- $ ./runInstaller
Start Oracle Universal Installer from patch set and select the ORACLE_HOME that you want to patch from the list and click next…next…to complete the installation. Run the $ORACLE_HOME/root.sh script as the root user, when prompted.
For Windows:- Start the OUI by running SETUP.EXE from patch set and select the ORACLE_HOME that you want to patch from the list and click next… next…to complete the installation
Step 6: Startup the listener.
$ lsnrctl start
Click here for steps to Upgrade Oracle Database to 10.2.0.4