Running different builds on Cluster

I would like to update a host in our 4.1 ESX Cluster using the update manager, there are 3 in the cluster, but keep the other 2 in the older build. Mostly this is to make sure the update doesn't cause any issues. Can the cluster work ok with different builds on hosts? Will HA and vMotion still work as intended?

All vm host and vCenter are at 4.1

If the update works ok, I would then update the second host after a couple of days, and finally the 3rd one.

Thanks for any help provided.