For hosts with RDM disks, please set the RDM disk  parameter “ IsPerenniallyReserved” to true before the patching.

http://pingforinfo.com/powercli-script-to-set-perennial-reservation-to-all-rdm-luns-in-a-cluster/

Three useful website for VMware patch version.

https://kb.vmware.com/selfservice/search.do?cmd=displayKC&docType=kc&docTypeID=DT_KB_1_1&externalId=2143832

https://esxi-patches.v-front.de/ESXi-5.5.0.html

https://my.vmware.com/cn/group/vmware/patch#search

Create a Baseline for the Patch

ESX Patch Version