The iPhone 4 had one of the cheekiest glitches to hit the smartphone.
Every iPhone since the original has come equipped with a proximity sensor that detects when you put the phone to your ear. In theory, when you use the iPhone as a phone, the screen shuts off so that you don't accidentally select any of the on-screen options that could disrupt a call, like "mute," "hold" or "end."
But iPhone 4 users complained that the sensor in the iPhone 4 didn't work properly, causing the device to accidentally drop calls or dial numbers mid-conversation.
After thousands of commenters posted to Apple's forums, the company fixed the issue with a software upgrade.
It's got Siri, a fancier camera, a better processor and Sprint, but is it worth the upgrade?
