You can upgrade the vCloud Usage Meter appliance by using an .iso image that includes a complete Photon OS update.
If you want to upgrade from vCloud Usage Meter 3.6.x, you must install vCloud Usage Meter 4.8 as a new appliance.
If you want to run in parallel both old and new appliances for a full reporting period, set the vCloud Usage Meter 4.8 instance to Test mode. You can still collect, aggregate, and reference the product consumption data from the vCloud Usage Meter 4.8 instances.
Then if you want to activate vCloud Usage Meter 4.8 for reporting, through the VMware Cloud Services Console, update the mode of the vCloud Usage Meter 4.8 instance from Test to Production.
To upgrade the vCloud Usage Meter appliance, you must install only the official vCloud Usage Meter updates that VMware provides.