Thanks for the answer.
Now I have two hosts 4.2.6 and 4.2.8, and the engine 4.2.6. VMs migrate between these
hosts without problems. But the VM with the engine to migrate to host 4.2.8 refuses - he
say:
No available Host to migrate to.
Since it cannot migrate, there is no way to put the host in maintenance mode. And there is
no possibility of upgrade.How to find out why? Install Host 4.2.6?