Upgrading Zerto Virtual Replication : Upgrading or Reinstalling VMware Components : Upgrading a vCenter Server
  
Upgrading a vCenter Server
Zerto recommends that you upgrade a vCenter Server rather than reinstalling it.
When upgrading both vCenter and an ESX/ESXi, you must first upgrade the vCenter.
Zerto Virtual Replication components are not affected by a vCenter Server upgrade. Protection continues and no additional procedures are required.
When upgrading a vCenter Server, make sure that you preserve the vCenter database. Preserving the existing database is required in order to continue using the existing Zerto Virtual Replication installation.
Note: If the recovery vCenter Server service is stopped, recovery operations are not possible until the service is restarted.