As others have said, you will need IPv4 to reach some services, NAT64/DNS64 at the edge could work for that.
Also, embedded system support for IPv6 is iffy. I know at some point Rokus wouldn't use IPv6 if IPv4 is present, if that's still the case, it may be that they won't use IPv6 even if that's the only thing available.
Also, embedded system support for IPv6 is iffy. I know at some point Rokus wouldn't use IPv6 if IPv4 is present, if that's still the case, it may be that they won't use IPv6 even if that's the only thing available.