87 is good battery health bro if u really interested to upgrade then purchase otherwise wait for an year than buy 16
They will also add action button to base model’s in iphone 16
Ofcourse , the exchange value depreciate further
If u want to purchase new mobile in apple store or apple site than mostly u need to buy 15 only with 16 I don’t think they will provide exchange value for 11
Even in this scenario u can wait until june or july which will reduce the price of 15 and u will get exchange value