I think it's pretty safe to say that it'll be a 6"s" model...meaning no exterior changes, but some major interior ones. At least that is what the leaks & history suggest. Everyone waits and lusts after the big number changes aka 4,5,6,7 etc...but A lot of the best upgrades are in the "S" models. That's when Apple seems to perfect the current numbered iphone by adding new features.