Apple had a much more improved guts in 5S. The Software design changed but the Hardware design remains the same. They introduced Fingerprint Scanner and flattened out the Home button but it still is outdated. Check out why?
Apple has retained a similar form factor since iPhone 4 but got a lot thinner, lighter and longer. It beefed up to 4-inch display but it has the same Box Shaped structure. Now, the problem with Box Shape is that it’s very contrary to the shape of our hands. HTC brought this to light with HTC One. It has a nice-curved back (imitating our palm) and inclined edges (like our fingers) which made this 5-inch phone almost organically fit our hands.