iPhone 5 wasn't announced during Apple's Oct. 4 press event, but iOS 5 was on full display.

Though some people might be disappointed with the announcement of the iPhone 4S, the new mobile OS has some really impressive features that will be implemented on the new device. Some older iPhones and the iPad will also get an iOS5 update.

Here are a few of the changes coming out on the new mobile OS. Start the slideshow to begin.