Hi Andy thanks for the great work creating a fork!
I just upgraded from generic-pc-1.8.2b78 to generic-pc-1.10.2b97(i386) and noticed that dhcp was failing. The log gave the following error:
dnsmasq[86]: Failed to start up
dnsmasq[86]: bad dhcp-range at line 11 of -var-etc-dnsmasq-dhcpd.conf
(offtopic: strange but when I use a slash forward instead of an - this post here in the forum won't save and I get an error...)
I downloaded the dhcpd.conf using the exec.php and had a look at line 11
dhcp-range=set:opt2,192.168.5.10,192.168.5.20,static
The word static seemed out of place. When I removed the checkmark at Deny unknown clients (Opt2 Services: DHCP server) in the GUI, the error (after a reboot) was gone and DHCP worked fine.
Then I downloaded the dhcpd.conf again and the word static was gone, so my preliminary conclusion is that they might be related.
I hope it's not a bug and it's just my configuration, if not I hope this post helps

Best Qinn