I'm trying to install Hub on an Ubuntu 16.04 system running dual stack. For a variety of reasons my local user machines can only access the IPv4 interface. However, Hub only listens on the IPv6 interface. I can't find any documentation that says if it's possible for Hub to listen on both stacks - is this possible? How? Barring both stacks, IPv$ is preferred and I have not figured out how to do that either.