And yes, four years since the first phone Apple has emerged. 4 generations of iPhone, each with their development.
These developments often criticized as too few to each model, are more interesting put together. So let us look back to see that has changed in four years, a material or software point of view.
The first iPhone (aka iPhone 2G) has a brushed aluminum back face and was equipped with the very first version of the iPhone OS. At the start no appstore which greatly limits its use. Then came the iPhone 3G, with a black or white plastic body, a 3G chip, GPS. The appstore was born and gave a boost to use. Then came the birth of the iPhone 3GS which incorporates the design of the 3G iPhone with a faster CPU and a compass. Finally the iPhone 4, with an entirely revisited design, the addition of a front camera, a better screen and a still camera more efficient .
Small changes of course but who have made the iPhone what it is today!