Sounds like this is exactly that. Too bad they didn't do that first, and we've had a couple decades of failing to widely adopt IPv6 because it's too complicated and confusing.

"1.7. Backward Compatibility and Transition

IPv4 is a proper subset of IPv8:

IPv8 address with r.r.r.r = 0.0.0.0 = IPv4 address Processed by standard IPv4 rules No modification to IPv4 device required No modification to IPv4 application required No modification to IPv4 internal network required

IPv8 does not require dual-stack operation. There is no flag day. 8to4 tunnelling enables IPv8 islands separated by IPv4- only transit networks to communicate immediately. CF naturally incentivises IPv4 transit ASNs to upgrade by measuring higher latency on 8to4 paths -- an automatic economic signal without any mandate."

Did you read the proposal? It proposes 64 bit address space.