The last version for that switch is 18.01.08 from 2015. You're running 18.01.01. Release notes for 18.01.08 don't show any added features so you may be out of luck with DHCP relay. You could configure the AD server's port as a trunk and pass both subnets to it on VLANs so that it has a presence on the VoIP subnet.
We put our DHCP relay statements on the core router between subnets. I would not think it mattered what firmware the switch had.