You can upgrade vSphere Replication 5.5.x, 5.8 and 6.0.0.x to vSphere Replication 6.x.

To upgrade a previously installed version of vSphere Replication to vSphere Replication for Disaster Recovery to Cloud, you must mount the vSphere Replication ISO file on a system in your environment that is accessible from the vSphere Replication appliance, and apply the update through the virtual appliance administration interface (VAMI) on port 5480. See Upgrade vSphere Replication by Using the Downloadable ISO Image.

After upgrading the vSphere Replication appliance, you must configure it to synchronize with an external NTP server. See Configure NTP Synchronisation in Your Environment.