> Yes, I like that better than broadcasting the exact height starting at
> which you serve (though I would put that information immediately in the
> version announcement). I don't think we can rely on the addr broadcasting
> mechanism for fast information exchange anyway. One more problem with this:
> DNS seeds cannot convey this information (neither do they currently convey
> service bits, but at least those can be indexed separately, and served
> explicitly through asking for a specific subdomain or so).
>

That's true, but we can extend the DNS seeding protocol a little bit - you
could query <current-chain-height>.dnsseed.whatever.com and the DNS server
then only returns nodes it knows matches your requirement.

This might complicate existing seeds a bit, and it's a bit of a hack, but
protocol-wise it's still possible. Of course if you want to add more
dimensions it gets uglier fast.