I phone 6 s plus is lagging due to software updates or lacking in massive hardware updrades?.reason for asking is because the 6s plus 128gb is a little over$500 in my country compared to the 7plus which is twice as much.and there’s probably gonna be a complete redesign in 2k18 for iphone so i’d rather buy the cheaper 6s plus. I strongly advice you reach out to Apple Customer Service as the upgrade to the new iOS 10, if that is the upgrade you refer to has had issues with the iPhone 6 - iPhone 6S Plus. Seems the iPhone 7 and up were truly designed to utilize the new iOS.