I need to disconnect (2) ESXi 6 hosts from a vCenter 6 appliance and add to a new vCenter 6.5 appliance, both which run on one of the hosts. Simple set up. No distributed switch and no cluster. Seems straightforward to disconnect then add to the new vCenter appliance. However, please let me know if there are any caveats going from vCenter 6 to 6.5 or adding ESXi 6 hosts to vCenter 6.5. FYI, some VMs on these hosts are version 8 VMs. Not sure if that matters outside of some management not being available. I am also doing this during business hours so please let me know if it's better to wait until after hours (which I usually do for anything on production servers but I was asked to do it asap if possible).