To check the firmware or software version on your Apple device (including iPhone, iPad, or iPod touch), you can follow the steps below on your device or check while your device is connected to a computer.
On your device:
To upgrade to the latest software version, follow the instructions at http://www.apple.com/iphone/softwareupdate/.
Connected to a computer:
iTunes should tell you if your software is up to date or if you need to upgrade. Click the Check for Update button to update your software version.