Isilon one fs 7.2 upgrade and SMB 2 client connection availability.

Would the windows 7 clients running smb 2 get disconnected during one fs 7.2 node upgrades ? The clients that have connection to any node that gets upgraded and rebooted would get disconnected ? My understanding for continuous client availability during node reboots if they need to be on smb3 or windows 8 or windows 10 ? is this true ?