[bradley13]

And the people who designed IPv6 designed a beautiful, perfect protocoll that was incompatible with the old IPv4 protocol. Which meant that a graceful, gradual shift to IPv6 was impossible. Cheap IoT devices are still being manufactured that support only the old protocol.

[orangeboats]

Oh boy do I have a great news for you!

https://en.wikipedia.org/wiki/Thread_(network_protocol)

Some IoT devices are now IPv6-required.