"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
T-Mobile Adds Apple Music to Music Freedom, Offers Free 'iPhone 6s' Upgrade With iPhone 6 Trade-In
T-Mobile also announced that customers who purchase an iPhone 6 for $15 per month through the JUMP! On Demand trade-in program will be automatically eligible to receive a free upgrade to the next iPhone -- the so-called "iPhone 6s" -- when it is released, with the $15 monthly promotional price carrying over to the new smartphone.
Purchasing an iPhone 6 through JUMP! On Demand will also land you priority access to the next iPhone, when T-Mobile receives inventory of the next-generation device, for those that upgrade within the first 48 hours of availability. T-Mobile claims these two new Apple promotions are the last of the carrier's Un-carrier Amped moves this summer.