Initiate the upgrade
Just as you can back up your device via iTunes or directly from your device to iCloud, so too can you update your iPhone, iPad, or iPod touch through an iTunes connection or via iCloud. The latter is easier as you can do it over any Wi-Fi network and needn’t be within cable-reach of your computer. Still, we’ll show you how to do it both ways.
Install over the air
When a new iOS update becomes available, it isn’t long before your iPhone, iPad, or iPod touch learns about it. Similar to the way the App Store seeks out new versions of apps you own, your device checks in with iCloud to see if a new iOS update exists. When it learns of such an update, a small red badge appears atop the Settings icon on the home screen.
To install the update, go to Settings > General > Software Update. On the resulting screen you’ll be told that iOS 8 is available. Tap the Install button to start downloading and installing the update. (If you don’t see the red badge on the Settings app but know that iOS 8 has been released, navigate to Software Update anyway. When you get there, your iPhone, iPad, or iPod touch will query the update server to see if a new version is available. If so, it will offer you the opportunity to install it.)
It’s a good idea to update your device only when it has at least a 50 percent charge or, better yet, is plugged into a power outlet. You don’t want your device to run out of power when it’s half-way through installing a new version of its operating system.
Install from your computer
If you happen to be within reach of your computer you’re welcome to install iOS 8 via iTunes. To begin, launch iTunes. If you’re not using the Wi-Fi Sync option, string the syncing cable between your computer and your iOS device. iTunes should tell you that a new version of iOS is available for your device and offer to install it for you. If you see such a notice, choose to install the update.
If iTunes doesn’t mention the update, click on the Summary tab and then click the Check for Update button. This will cause iTunes to query Apple’s servers about the existence of any new updates. When it’s alerted to one, you’ll be told that the update is available. To install it, click the Update button. iTunes will then start downloading the appropriate version of iOS for your device. (Apple creates different versions of iOS 8 for each device and model. So even though you’ve download one copy for your iPhone 5s, you’ll need to download a different version for your iPad mini.)
Regardless of whether you choose to update iOS over the air or via iTunes, it should only update the operating system and Apple’s default apps. Any other apps and data on your device will be preserved in their current states.
Starting over with iTunes
If you’re the kind of person who uses a major iOS update as an excuse to start fresh—with a device that behaves as if it just came out of the box—you have the option to completely wipe the apps and data from your iPhone, iPad, or iPod touch; install iOS 8; and then operate it as if new (or restore it from a backup). One avenue for doing this is via iTunes.
To proceed, in iTunes’ Summary tab, instead of clicking Check for Updates, click the Restore button (Restore iPad… or Restore iPhone…, for example). If Find My iPhone/iPad/iPod is switched on you’ll be asked to disable it (as described earlier). If you have purchased media on the device that hasn’t been backed up to iTunes, you’ll be prompted to do that. You'll then be asked if you're really sure that you want to restore the device to its factory settings. If you're certain you have a backup, go right ahead.
Again, iTunes will download the version of iOS 8 appropriate for your device and then install it. During the installation you’ll see the Apple logo on the face of the device and a progress bar, giving you a general idea of how long it will take to install iOS.
iTunes will display a series of messages, telling you it’s waiting for your device to get ready, verifying that the device can work with that version of iOS, and then telling you that it’s restoring your device.
When iOS is finally installed, iTunes offers two choices. You can set up the device as a new one—meaning your device will be set up as if you’ve just pulled it from the box. Or you can enable the Restore from this backup option and then, from the pop-up menu, choose a backup you’ve created. (Ideally the latest backup you’ve performed.)
Set up as a new device
Choose Set up as new iPhone/iPad/iPod and click Continue and you’ll be walked through the process of setting up the device just as you did when you first got it. The first thing you’ll see is your device welcoming you with a cheery “Hello” (or a greeting in another language). Do as the screen tells you and slide to the right to get started.
This begins a process where you’re presented with a variety of setup options. They include choosing a Wi-Fi network, agreeing to Apple’s terms and conditions, choosing to use location services, entering your Apple ID (or creating one if you don’t have such a thing), choosing to use iCloud, enabling the Find My feature, selecting identities to use with iMessage and FaceTime, choosing and confirming a passcode, allowing your device to use iCloud Keychain, choosing to use Siri, and deciding whether or not you want to send diagnostic and analytics data to Apple and third-party developers. If you’re unsure about what a particular option does or means, there’s generally a bit of text that explains it (or a link to more information). A Back button is available on every screen so if you've made a mistake, just retreat through your previous steps and correct the issue.
If you have an iPhone with Touch ID security you’ll be prompted to scan one finger during the setup process. You can skip this step if you like.
It takes about five minutes to walk through the process and the only information you'll need is your Apple ID and password and the password for your Wi-Fi network, if one is necessary.
Starting over via Wi-Fi
iTunes is just one way to set up the new OS. The other is to switch on your device, connect to a Wi-Fi network, and then start the setup process. When you do, you’ll arrive at a Set Up screen where you can choose to set up the device as a new one, restore it from an iCloud backup, or restore it from an iTunes backup. If you choose the last option, you’ll be prompted to connect your device to your computer. We’ll examine this option first.
Restore from iTunes backup
If you choose to restore from an iTunes backup, connect the device to your computer, select it in iTunes, and from the Restore from this backup pop-up menu choose the latest backup for your device and click Continue. Your device will display the Apple logo and a progress bar, indicating that it’s being restored from the backup. When that’s complete the screen displays an Update Completed message. Tap Continue and you’ll be walked through a few steps—enabling location services, choosing accounts to use with iMessage and FaceTime, creating and confirming a passcode, and choosing to share analytics data with third-party developers.
When the update completes, iTunes will copy your backed-up apps and data to the device. Depending on how many apps you have, this could take many minutes.
Restore from iCloud backup
If you’ve backed up your iOS device to iCloud (rather than to your computer via iTunes), select Restore from iCloud Backup on the Set Up screen. You’ll be prompted for your Apple ID and password. Enter them and tap Next. Your device will sign into iCloud and you’ll be presented with the Terms and Conditions screen where you tap Agree twice.
Choose the desired backup (you may have more than one depending on the number of iOS devices you’ve backed up), and then wait; the process can take anywhere from a few minutes to many hours, depending on how many apps you had installed and how much data you had stored in those apps. (As mentioned earlier, restoring from an iTunes backup is much faster than restoring from iCloud, which is why many people back up to iTunes periodically even if they normally back up to iCloud.)
When the restore is finished, your device restarts, and you see a screen explaining that you have a few more steps to follow. These steps include entering your Apple ID’s password again, selecting which identities you want to use for iMessage and FaceTime, creating a passcode, and setting up iCloud Keychain.