There weren’t practically changes in the design.
The company said it had "decided to go back to basics". They kept the same formula as the Galaxy S III and the Galaxy S4 but with a few cosmetic changes. Metal body design? Nope. The device now has a pebbled silver back that looks like it's metal but is actually polycarbonate. Samsung calls it "perforated" and also a "modern glam look." It still has the home button but has been designed to maximize screen real state to show off Samsung’s display technology.