While upgrading from 8121 to 11, after executing Updatemanager.bat and if the update fails, You need to check the Updatemanager logs in the path < Support Center Plus Application path -> Server-> Default-> Logs > .
And if you find the below mentioned error trace in the logs, you need to follow the solution given below.
[SEVERE] : Problem during upgrade.java.lang.RuntimeException: PostgreSQL upgrade sanity failed.
In version 8121, edit the updatemanager.bat file that will be present under the Path <ManageEngine\SupportCenter\bin> folder and add the below given entry as shown in the snapshot
After entering the entry save it and close it.
Continue with the migration in a new setup. Make sure you do not upgrade in the failed setup again.