How do you have 10 clue scrolls ? <| sep |> I guess these don ' t need to since we got v 4 , right ? Since IPv 6 is not backward compatible with IPv 4 , devices that only understand one of these protocols will be unable to communicate with each other . This means those gazillion devices can communicate with each other and with every device understanding both versions but can ' t talk to something that is only IPv 6 . Right now this isn ' t an issue since probably every IPv 6 device will also be able to use IPv 4 . but when we ' ve got devices that can only use IPv 6 , we ' ll start to get two versions of the internet that are not really compatible with each other . Now of course , probably every device that can use IPv 6 can also use IPv 4 . but this won ' t matter when we run out of IPv 4 addresses . At that point those devices will not be able to use their knowledge of IPv 4 as they won ' t have an address to communicate on .