iOS is the mobile operating system for the iPhone, iPad, and iPod touch. For best performance, check and update all iOS software on your iPhone, iPad, or iPod touch to the latest versions:
Determine which iOS software your device uses: Tap Settings > General > About > Version.
Update the iOS from your computer: Connect your device to your computer and install the latest version of the iOS using iTunes.
Update the iOS from your device: Tap Settings > General > Software Update.