Besides the new iPhone 5S and iPhone 5C, you can install iOS 7 on iPhone 5/4S/4, iPad 4/mini/3/2 and iPod touch 5. If you want to update to iOS 7 or iOS 7.1 for your iDevice after figuring out the answer for the question " should I upgrade to iOS 7", then follow the 2 methods below.
How to Update to iOS 7 on iPhone, iPad, iPod Touch - 2 Easy Ways
You can update your old or current used iPhone, iPad, or iPod touch 5 to iOS 7 or iOS 7.1 with iTunes or though Wi-Fi (over the air). Yet, there are some tips you need to pay attention to before iOS 7 upgrade.
Tips before iOS 7 Update on iDevice
1. Backup your iDevice. Updating to iOS 7 on your device could cause data loss, like contacts, photos, messages loss. Therefore, you need to backup all of your data before upgrade. Refer to the article Backup iPhone 7/6s/6/6 Plus/5S to use the same methods to backup your current device.
Note: If you forget to backup your device before updating to iOS 7, go to iPhone Data Recovery to recover the lost data from iPhone, iPad, or iPod touch after updating to iOS 7.
2. Clear some space on your device. The iOS 7 update is around 600 MB to 935 MB in size for different devices and needs at least 3 GB of storage to successfully update. Check to see if you have enough available space. If not, delete some unimportant data and unused apps to clear the space.
3. Restart your device. Restarting your device could help to reduce the chances of frozen updates and install failures.
Ways to Upgrade to iOS 7
After you have performed all the tips above, you can start right now to use the 2 ways to install the new iOS 7 on your device without UDID or developer account. Here are the 2 ways on how to download iOS 7 and how to update to iOS 7 free.
1. Use iTunes to Update to iOS 7
Update iTunes to the newest version 11.1 by opening iTunes on your computer, clicking iTunes > Check for Updates.
Connect your device to computer with a USB cable, click on your device in the upper-right corner of iTunes and then click the "Update" button.
Click "Download and Update" button in the pop-up window which informs you the new iOS 7 is available.
In the process of updating, keep iPhone connected to the computer until your device restarts. After restarting, your device will greet you in any number of languages with the iOS 7 setup screen. Make your settings as you like.
2. Use Wi-Fi to Install iOS 7
Connect your device to a Wi-Fi network.
Go to Settings > General > Software Update on your device, and click "Download and Install" button for iOS 7.
Tap to agree to Apple's terms and conditions. Heed or ignore Apple's advice to connect your device to a power source during to download to save battery.
Tap "Install Now" after iOS 7 is downloaded. After installation, your device will restart and you need to set up iOS 7 by following the setup screens.
What If You Fail to Update to iOS 7
You may fail or run into some issues with Apple's servers, such as you may get an error massage "Software Update Failed", or "Software is unavailable at this time". The reason is reported to be that millions of iOS device users are updating at the same time and getting slammed in traffic. Try for several times until you finally complete to download and install iOS 7 on your device.
Select one of the 2 methods and follow the instructions step by step to install iOS 7 on your device. You will never be trouble with the question "how do I update to iOS 7". If, in some cases, you don't feel like the new iOS version, downgrade from iOS 7 to iOS 6 right away.