I personally would have added one additional byte, but when it is written I would have added two bits to each of the original bytes. That has the advantage of making each segment 0-1023. I would have reserved the 1000-1024 values, such that IP addresses look the same visually: 476.188.049.772, but the available number is increased by a factor of more than 200. Maybe it’s not too late to release IPv5…