While trying to upgrade from 9.6 to 11.6 it is failing with this below error:
su - postgres -c '/usr/pgsql-11/bin/pg_upgrade -d /opt/collabnet/teamforge/var/pgsql/9.6/data -D /opt/collabnet/teamforge/var/pgsql/11/data -b /usr/pgsql-9.6/bin -B /usr/pgsql-11/bin'
Performing Consistency Checks
Checking cluster versions ok
The source cluster was not shut down cleanly. Failure, exiting