On: We're about to hit phase 3 of ARIN IPV4 rationing

[sp332]

Dual-stack still requires an IPv4 address.

[nknighthb → sp332]

Of course it does, but not necessarily a publicly-routable one. Dual-stack is necessary because otherwise the IPv4 application literally won't run at all. How the packets actually traverse the public internet is a different matter addressed by things like NAT, proxies, or tunnels.