Now here are the conditions. Those switching to T-Mobile must activate two new lines of service, one of them for the new device. That’s it. Existing T-Mobile customers must activate at least one new qualifying line of service, and trade in a handset (more on that later). Whether you’re a new or existing subscriber, the new handset must be bought using an EIP, and any down payments or taxes must be paid at the time of purchase.
If you are a T-Mobile customer, you will need to follow these conditions for your trade-in. If you’re buying an Apple iPhone, the trade-in must include one of the following models:
All trades must be in good working condition with no liquid or physical damage. Find my iPhone and any Android anti-theft features must be disabled when turning in the trade.