single-path iSCSI setup incurs downtime during HA node upgrade?

Environment:

ONTAP 9.1 on an HA pair

Windows Server 2008 R2 (no MPIO installed)

Hi,

I have an iSCSI LUN that's accesbile via an ifgrp on a node. When I upgrade the node in the HA pair, doesn't the interface fail over to other node therefore there is no downtime? In other words, even though I don't have MPIO set up to access both nodes, the iSCSI connetivity should not go down during the failover and giveback?

Thanks,