On Mon, 14 Dec 2015 04:10:34 +0000 (UTC)
<lloyd(_dot_)wood(_at_)yahoo(_dot_)co(_dot_)uk> wrote:
IP protocol version 5 is already defined and in usefor RFC1190, and
that use would have to be deprecatedfirst. Picking 7 is easier; for a
long time someoneon this list was pushing an idea of IPv8... and IPv9.
I believe the IPv8 you are referring to was hardly a serious proposal.
Regardless, 7, 8 and 9 were reserved for TP/IX, PIP and TUBA
respectively.
<https://www.iana.org/assignments/version-numbers/version-numbers.xhtml>
John