No (this is again absolutism, there is many ways to upgrade, i.e. we are speaking to skype dudes to see how they did it etc.) , any node could speak both language A and B and via multiformat or other means know which language to speak. This is RFC territory though and that RFC does not yet exist.
I appreciate that (a lot), but I think this list does not come across as us being clever in any way. It is a set of principles/foundations the network requires in our opinion. It has not changed but we felt it did need re-emphasising. Your explanations make it sound as though you are trying to be clever telling us there is only one way and then creating that way in what really needs to be a design discussion/doc (RFC). All we are saying is the network needs upgrades and may …
Whichever one is waiting at the time we want one in a section. Nodes will try-join and be accepted or rejected (probably do resource proof work etc.). Again though RFC
I don’t agree, after all it is designed to. This is why so much work in crust with NAT traversal and reliable udp etc.