The update are a pair of graphics-related fixes one for an occasional glitch on the 4th-generation iPod touch and one for flickering problems when using the Apple Digital AV Adapter with some TVs. It also resolves a problem with authenticating some enterprise Web services and some bugs experienced when activating and connecting to cellular networks.
The update is recommended for GSM iPhone 4, iPhone 3GS, iPad, iPad 2, and the third- and fourth-generation iPod touches. To download and install it, connect your device to your Mac or PC and click Check for Updates in iTunes. then you will get the latest version of iOS 4.3.1 mobile operating system.