Have the iphone 6 plus with ios 9 and had no problems at all, also downloaded the ios 10 and looks and works okay. Pre-order the new iphone 7 plus witch is due to come around Oct 11, so will see how that goes.
(This iphone 6 plus was my first ever apple stuff, have being a loyal member of the android phones, and off course the note from samsung , but to many problems i had with it.)