A:AnswerNot certain if at&t still offers the 6s or 6s plus models but if so then yes you can trade in towards the purchase of them. You may not like the trade in value they will give you towards the iPhone though. I would sale the S7 to an individual and just purchase one straight out. Refurbished starting at 125.00 and new unlocked around 300.00. Hope this helps.
