added note warning users to update vSphere for 4.12 to 4.13 updates

Author: obrown1205

updating/updating-hardware-on-nodes-running-on-vsphere.adoc

@@ -10,11 +10,21 @@ You must ensure that your nodes running in vSphere are running on the hardware v
 
 You can update your virtual hardware immediately or schedule an update in vCenter.
 
+[IMPORTANT]
+====
+Before upgrading Openshift 4.12 to Openshift 4.13, you must update vSphere to *v7.0.2 or later*; otherwise, the Openshift 4.12 cluster is marked *un-upgradeable*.
+====
+
 [id="updating-virtual-hardware-on-vsphere_{context}"]
 == Updating virtual hardware on vSphere
 
 To update the hardware of your virtual machines (VMs) on VMware vSphere, update your virtual machines separately to reduce the risk of downtime for your cluster.
 
+[IMPORTANT]
+====
+As of Openshift 4.13, VMware virtual hardware version 13 is no longer supported. You need to update to VMware version 15 or later for supporting functionality.
+====
+
 include::modules/update-vsphere-virtual-hardware-on-control-plane-nodes.adoc[leveloffset=+2]
 include::modules/update-vsphere-virtual-hardware-on-compute-nodes.adoc[leveloffset=+2]
 include::modules/update-vsphere-virtual-hardware-on-template.adoc[leveloffset=+2]