2.2 is over-the-air, directly on their device. It’s fast, it’s efficient, and it’s simple to do.
1. Make sure you have a recent iCloud backup.
2. Launch Settings from your Home screen.
3. Tap on General.
4. Tap on Software Update.
5. Tap on Download and Install.
6. Enter your Passcode, if prompted.
7. Tap Agree to the Terms and Conditions.
8. Tap Agree again to confirm.
The download will begin automatically. If the download does not begin right away, you may see a notice: “Preparing to download.” Give it a couple of minutes and the download will begin shortly.
How to install iOS 11.3 using iTunes on your Mac or Windows PC
If you have limited space on your device or software update isn’t working for whatever reason, you can update using iTunes.
1. Make sure you have a recent iTunes backup. Make it encrypted so all your password and other private data is preserved.
2. Launch iTunes on your Mac or Windows PC.
3. Plug your iPhone, iPad, or iPod touch in using your USB to Lightning or USB to 30-pin Dock cable.
4. Click on the device icon at the top left to go to the device tab.
5. Click on Check for Update in the Summary pane.
6. Click on Download and Update
7. Agree to the Terms and Conditions.
8. Enter the Passcode on your iPhone or iPad, if prompted.