What I mean by this is, the iPhone 4 was released in 2010, on iOS 4. By the time of the iOS 7+, 2013 or later like 2015 or 2016, it becomes slow and "weak" it seems, not sure if the advance iOS software (iOS 7) has anything to do with it or if websites' software themselves become more advance. What I mean is, when you go onto a website in 2016 on an iPhone 4, it feels like it takes 3 seconds longer to load, the website or sections of the website while you're scrolling up and down the websites. When you swipe the screen, there is a lag time of between 1-3 seconds and THEN the website moves. Sometime, a website is "too advance" or maybe "too demanding", your browser would shut down, like Safari or Google Search. So essentially: 1) Websites and sections of websites take longer to load, up to 3 seconds. 2) There is a lag when you swipe and then the website responds, up to 3 seconds. 3) Safari/Google Search shut downs when trying to handle websites sometimes, because their software is too demanding or advance? 4) Links do not respond when you press on them, links like "General Discussion" or "Off-topic Discussion" of forums. This happens on the iPhone 4 in 2016, and it's quite a sub optimal experience, very frustrating. It makes you want to upgrade. I am, again, not sure if it's the iOS 7 itself, the websites' software, or a combination that caused the 4 afflictions. So basically, what I am asking is, when will the iPhone 5S become like the iPhone 4? should I expect "three years" or "three iOS" upgrades for the iPhone 5S to become like the iPhone 4? So once the iPhone 5S upgrade to iOS 10, which is 3 from the original iOS 7 as the iPhone 4 upgraded to iOS 7 from iOS 4, the iPhone 5S will suffer the 4 problems listed of the iPhone 4? if this is so, is it wiser to stay permanently at iOS 9, or less, and never go to iOS 10 for silky, buttery, smooth website browsing with no lag in loading, swiping, no shut down, and unresponsive links? Thx again, any insight would be good, I mean for giving me a year estimate for when the iPhone 5S will become like the iPhone 4 or whether I shouldn't upgrade to newer iOS, iOS 10, for the iPhone 5S. Thx again.