Ah okay. So the point of prefixing IPv6 with IPv4 is that if the ISP has only IPv4 switching, it will only grab the first 32 bits of the IPv6 address... which is the IPv4 address. So no ISP changes needed.
Ok then we are left with my original question. What if my ISP does not own any routers implementing NAT64? Will iOS send IPv4 packets? I think the answer is yes.
