Using the vCenter 6.5 Migration Assistant 

To upgrade and migrate vCenter 5.5/6.0 components running on Windows Servers, vCenter 6.5 comes with a new tool named the vCenter Migration Assistant. The procedure to run the migration-assistant is the same whether you are trying to upgrade an external SSO, PSC, or Update Manager or an embedded version of these. The migration-assistant should be run on the machines hosting these services separately, before initiating the vCenter Migration/Upgrade. The migration/upgrade process will migrate data from all the components server with an active migration-assistant session.