Just ahead of the rollout of the newest iOS 10 free software upgrade which is expected in September, Apple has made available iOS 9.3.4 for compatible iOS devices.
The update is very small, weighing in at 25.1MB, but provides an important security patch for the iPhone and the iPad and is recommended for all users. According to security content of iOS 9.3.4, Apple has addressed a particular memory corruption issue through improved memory handling. Apple has given credit to the Pangu team for discovering the vulnerability.
If you own iPhone 4s and later, iPad 2 and later or iPod touch 5th gen and later, consider installing the update as soon as possible to patch the security flaw. To update your iPhone, iPad or iPod touch wirelessly, just plug the device to power and check for a stable internet with Wi-Fi. Head over to Settings>> General>> Software Update then hit Download and Install option. If you see a message asking you to temporarily remove apps as the iOS needs more space, just tap Continue or Cancel. You can always reinstall the apps that are removed.
Finally, tap Install. Alternately, you can schedule the update for a suitable time by clicking Later and choose Install Tonight or Remind Me Later. If you choose Install Tonight, just connect your iOS device before you go to sleep. Your device will update automatically overnight. Enter the passcode if asked to do so.
You can also update your device using iTunes. All you need to do is install the latest version of iTunes on the PC. Then connect your iPhone/iPad to the PC, launch iTunes and select your device. Click the Summary tab and click Check for Update. If the update is available, just click Download and Update and you are done.