We have two UCS server (UCS-C220-M3S ) and UCS-C240-M5 . Currently We have all the CUCM VMs on VMware ESXI 5.1 host on UCS-C220-M3S. We want to migrate all of them to new USC server (UCS-C240-M5) on host ESXi 6.5.
You can take DRS backup of all the applications and build the applications newly (CUCM, Unity Connection etc) and restore the DRS backup. This needs to be planned well, say when deploying CUCM PUB on the new UCS, shutdown the PUB on the existing/old UCS etc. Do check the compatibility matrix for the ESXi.
This is one way of doing, other options being taking the copy of the VMs and deploying it in the new UCS. Not sure whether this is Cisco supported.