The DHCPv6 service is now available for devices with a static IP address (those with IPv4 addresses from 137.138.0.0/16 or 188.184.0.0/15).
At the moment the service is available only for the devices that are marked "IPv6 enabled" in the network database (landb). If you want to try DHCPv6, please drop an email to ipv6@cern.ch stating the name of your device (landb name).