I work in IT... For a while now, Microsoft Server has been getting root hints for DNS and putting both IPv4 and IPv6 addresses in.
The NICs default to IPv6 addresses. My firewall (Cisco) supports it.
But my ISP (Charter Business Cable) does NOT without using IPv6 tunnel stuff, like offered from Hurricane Electric.
What does all this mean? Yes, it's coming, no you can't stop it. No, you cannot be backwards compatible.
Do you want to remain connected? Then accept our new IPv6 overlords....