Finally iPhone 4S was released this October but isn't so surprised as few changes on the iPhone 4S compared to iPohne 4. However acctually there are many difference between new iPhone 4S and iPhone 4.

Today let's focus on the mid chassis plate. The main difference is the antenna separation gap on the mid plate chassis. iPhone 4S mid chassis plate features four antenna separation gaps, one at each corner of the device. In contrast, the iPhone 4 mid plate only has three of these black lines.

Although these changes to the iPhone frame are likely a redesign of the antenna, it's not clear if the changes are to accommodate the Verizon Wireless LTE network or simply to reduce the attenuation issues experienced by some users. Apple decided to distribute free cases to iPhone 4 owners last year due to complaints that the iPhone 4 dropped calls when held a certain way.

The ensuing media storm was dubbed "Antennagate" even though the iPhone 4 external antenna design was more sensitive to low strength cellular signals. Those who are having problems with their iPhone 4 can still request a free case from Apple.

It shows that Apple moved the mute button down slightly to accommodate one of the antenna separation gaps. Both the iPhone 4S and iPhone 4 have SIM card slots in the same place.