Configurable VLANs are now available as 2.21.0 has been released to iOS and Android.
With this release VLANs are now available across all Meraki Go devices (GR, GS, GX).
As one of the make-a-wish topics mentions (https://community.meraki.com/t5/Make-a-Wish-Feature-Requests/Additional-DHCP-pool-on-GX20/m-p/97472#...), a new VLAN created on GX will not get a additional DHCP pool. Is this by design, or is this something you'll add soon?
I can understand the confusion presented here and for that I extend my apologies.
A new VLAN will have DHCP enabled by default. We will soon be introducing the ability to configure the new DHCP server in an upcoming release.