Using mand. DHCP in a lot of VLAN's in our network, experienced major issues.
Had to roll back to 18.107.6 as advised by Meraki Support.
Upgrading to 18.107.8 also resulted in an unstable network, switches, camera's, AP's no longer coming online.
Latest update from support:
"we have an issue with mandatory DHCP on firmware 18.107.7 and above, and it is still unresolved"