We are running a deployment of 4 ACS 5.3 instances on VMware ESXi version 5.0. We have not upgraded beyond ACS 5.3 as ESXi version 5.5 is required for ACS 5.4 and beyond. We wish to migrate to ISE 2.3 in a different VM farm running ESXi version 6.0. Would it be possible to take one of the 5.3 instances out of the deployment to make it standalone, upgrade it to ACS 5.5 (even though the ESXi version is not up to 5.5, but without the intention of ever authenticating anything against it), and run the migration tool against the ACS 5.5 standalone?
