In the past few years Apple has been selling their phones carrier unlocked with radios for all major carriers in the US. That being said this year is different. If you wanted an iPhone that will work on all the carriers you would have to pick up the Verizon variant which is the only variant that includes both GSM and CDMA radios. The only issue with this is that currently the Verizon version of the phone is dropping LTE at random.
MacRumors has reported that dozens of the devices are experiencing this bug. It looks like Apple has some work to do with this device. We have now seen a report of an exploding iPhone 7 Plus to go along with the radio issues. The big question is will Tim Cook go the route of Steve Jobs and tell consumers "You're holding it wrong!"? Maybe a simple update will resolve the issue.
via MacRumors