Upgrade VCenter

In order to ensure protection is not affected when upgrading or replacing a vCenter, the vCenter database should be preserved

Upgrade then make sure Replication all comes back green

Upgrade Hosts

Before Upgrading the Hosts to the latest ESXi , double check the current version of Zerto supports the version you are putting on or you will get the error on Upgrade “VRA unsupported esx version”

Migrate all VM’s to other VPG’s , migrate 6 VM’s at a time

Once VM’s migrated , shutdown VRA and VRAH , restart upgrade host

You can migrated VCC machines to other hosts without effecting replication

https://nolabnoparty.com/en/vsphere-6-7-upgrade-esxi-6-5-to-6-7-pt-3/