I upgraded my SG-4860 last night and it went fine, but it took well over 30 minutes to reboot. I'm not sure if there was some sort of UEFI boot migration or something unusual with this upgrade, but it was an unnerving delay. By the time I dug out a USB cable to try and rig up the serial console it had come back. I haven't seen any DHCP/DNS weirdness as others report, but my setup is a little bit weird there already.