Q: Are VMware's vSphere HA and Storage DRS supported in a mixed-version cluster?

vSphere HA might respond to a host failure by restarting a virtual machine on a host with an ESXi version different from the one on which the virtualmachine was running before the failure. A problem can occur if, at the time of failure, the virtual machine was involved in a Storage vMotion action onan ESXi 5.0 host, and vSphere HA restarts the virtual machine on a host with a version prior to ESXi 5.0. While the virtual machine might power on, anysubsequent attempts at snapshot operations could corrupt the vDisk state and leave the virtual machine unusable. (Best Practices for vSphere HA Clusters)