> What specifically do you mean by ipv6 support?
This question does not make sense. This is equivalent to asking "What specifically do you mean by ipv4 support"
These days both protocols must be supported, and if there is a blocker it should be clearly mentioned.
How do you want to allocate ipv6 addresses to containers? Turns out there are lots of answers. Some people even want to do ipv6 NAT.