The iPhone 4 much like older models of the iPhone is a smartphone with key features including a native mailing app, a web browser, SMS messages, a phone function, and an iPod among other things. The iPhone 4 comes in black and white. The iPhone currently runs iOS 7.1.2, but originally shipped with iOS 4.0. The iPhone 4 is currently only available in an 8GB model from Apple. On February 7, 2011, Verizon released a CDMA iPhone 4, ending Apple's exclusivity agreemnent with AT&T. You can also buy it carrier unlocked from Apple's website. The device can also be bought from AT&T and Verizon, the two U.S carriers who carry the phone.