Weblogic 10.3.5 to 10.3.6 in-place upgrade

Action:

Download and apply the upgrade patch

Steps

1. Download the upgrade patch from metalink. The patch number is 13529623. 

You can also search for the correct patch in metalink using the "Patches &   Updates" tab

In the "Patch Search" box provide the following details 

Oracle WebLogic Server as Product, 10.3.6 as Release, Linux X86 as Platform (Linux 64 bit was my platform) and  give Upgrade in the Description field to reduce the number of search results.

2. Unzip the downloaded file. 
The resultant file would be wls1036_upgrade_generic.jar file.

3. Backup MW folder and Inventory directory
Shutdown all the WLS services and backup the directories. Always good to     have the backup in place before a major upgrade.

4. Invoke the upgrade installer and follow the intrauctions in the installer
java -d64 -jar wls1036_upgrade_generic.jar

5. Choose "Use and existing middleware home" option and pick the current MW Home location for upgrade. All the screens are self explanatory.

6. Click complete.
Files will now be upgraded to 10.3.6.0 Maintenance level

7. Startup the Weblogic Admin server
The startup log will show the latest maintenance level of 10.3.6.0