Please confirm you are running Veeam Management Pack 8.0 prior to installing this update. You can check this in Operations Manager console under Administration | Management Packs, the build number should be 126.96.36.1998 or later.
To install the update, import the management packs through Operations Manager console > Administration > Management Packs > Import Management Packs.
To obtain Veeam MP 8.0 for System Center - Update 6, please download it here
It is important that you update Veeam Management Pack Core Services to Support TLS 1.2 Protocol for Update 6