Apple doc: https://support.apple.com/en-us/126101

Only Boost Mobile in the U.S. Weird. About 7.5M subscribers. Maybe it requires 5G? Wonder if it works when roaming?

https://en.wikipedia.org/wiki/Boost_Mobile

https://en.wikipedia.org/wiki/List_of_mobile_network_operato...

https://en.wikipedia.org/wiki/5G_NR