You should always perform a backup before applying any major new firmware release. If you back up your devices to iCloud or sync with iTunes via Wi-Fi, temporarily disable both options.
To disable iCloud backup, toggle the iCloud Backup switch to OFF under iOS Settings > iCloud > Storage & Backup. To disable iTunes Wi-Fi sync, tether the device to a Mac or PC via a USB cable and uncheck the “Sync with this iPhone over Wi-Fi” box under your device’s Summary tab in iTunes.
Make sure you’re running the most up-to-date version of iTunes (you should only download the latest version of iTunes from Apple’s website). Fire up the program and choose your device in the upper right part of the iTunes window. Should iTunes warn you there’s a new version of iPhone firmware update available, just cancel the prompt.
Click on the device’s name in the upper-right part of the iTunes window, navigate to the Summary tab and hit the “Back Up Now”. Fix yourself a cup of coffee as creating a backup on your computer may take a while, depending on its contents and storage capacity.
While we’re at it, update your iOS apps by going to the Updates tab in the iTunes Apps section. Now’s also a good time to copy the device backup file to an external drive (PC) or initiate a manual Time Capsule backup. To do the latter, just choose Back Up Now from your Mac’s menu bar. If you don’t see the option, tick the “Show Time Machine in menu bar” box in System Preferences > Time Machine.
To see where iTunes stores iOS device backup files on your computer, choose Preferences from the iTunes menu and navigate to the Devices tab. In case you were wondering, iOS backups keep all your app data and settings, sans your media and apps themselves because these items already exist in iTunes/iCloud.
Keeping a device backup on your computer is not only a precautionary measure, it’ll also speed up restoring your device should you encounter any issues – as opposed to restoring from an iCloud backup.
You’re now ready to install iOS 7: hit the Restore iPhone button in iTunes and wait until the software downloads and verifies the latest iOS 7 build with iOSDownload.
