iOS 12 is released tonight (17 Sept), bringing dozens of cool new features to any iPhone or iPad that can run it. In this article we show how to download, install and run the new version of iOS, as well as how to fix any problems. (If these prove especially tricky, read What to do if you can't update iOS.)

We'll start with some important preparation steps; but you can jump straight to the update process if you prefer. And if you change your mind, here's how to downgrade to an old version of iOS.

How to prepare your iPhone/iPad

Before you update to iOS 12, we recommend that you do the following:

  1. Back up your iPhone or iPad.
  2. Save a copy of iOS 11 - we explain how below.
  3. Clear some space on your device. Alternatively, you can update iOS via iTunes. If you don't have enough space, iOS may offer to temporarily delete apps to make room, then reinstall them afterwards.
  4. Plug your device into a power supply.
  5. Make sure you're downloading over Wi-Fi, not via 3G or 4G, or you may end up running out of data. Check it's a safe network (we don't recommend you do this over hotel Wi-Fi).

Save a copy of the old version of iOS

This bit is fiddly, but it will improve your chances of downgrading to the previous version if you change your mind later. (Note that even then it may not be possible. Downgrading is really tricky.)

Look in Library/iTunes and select the Software Updates folder for your device. (Access the Library folder in your user folder by holding down the Option/Alt key in Finder and selecting Go > Library.) If your Mac has deleted this file, launch your web browser and search for download ipsw. Make sure you get the right one for your device.

How to update iOS

Now to download and install the latest version of iOS.

  1. Go to Settings > General > Software Update. iOS will check if there's a new version.
  2. Tap Download and Install, enter your passcode when prompted, and agree to the terms & conditions.
  3. Your device will download the update in the background, and you can carry on with other things. Once the download has finished you will receive a notification.
  4. Tap Details. This will take you back to Settings > General > Software Update.
  5. Tap Install Now. This may take a while.
  6. Alternatively, you can select Later. iOS will offer to update during the night - you just need to make sure the device is plugged in.

How to upgrade iOS from a beta version

If you previously tried out a beta version of iOS ahead of its full release, you should note that in order to get upcoming non-beta iOS releases you will need to remove the Apple configuration profile from your device.

You can do this by going to Settings > General > Profile and selecting iOS Beta Software Profile, then choosing Delete Profile and entering your passcode to confirm the change. From now on you will receive official updates (rather than beta updates) as normal.