Question: are 5g phones compatible with 4g?
Answer: For either sub-6 GHz or mmWave, it's important to remember that early 5G phones can also use 4G. In fact, most 5G phones currently have the most advanced version of 4G (LTE Advanced Pro) built-in, which means you're going to get the best possible 4G experience on those phones if you do fall outside 5G coverage areas.