It is not necessarily to have IPv6 support. It is enough to be able to send the AAAA records to the registries. When this option will be available somehow, I will start to transfer all my domains to Dynadot and I will get a Bulk credit. Thanks.
For this to be properly enabled, Register a domain name server should take both an IPv4 and an IPv6 address for a single nameserver entry (e.g. ns1.example.com), for the domains that you can provide IPv6 glue for. (e.g. .com, .net, .org)