[RKearney]

Fortunately public facing systems are capable of being dual stacked so that won't be a problem. There's no reason internal networks can't be v6 only. Microsoft's already done it.

[IvyMike]

I know they have plans:

https://teamarin.net/2019/04/03/microsoft-works-toward-ipv6-...

But AFAIK that is still aspirational. I would be pleasantly shocked and impressed if they had already achieved that.