iPhone operating system updates are released free of charge by Apple occasionally. The newest version, iOS 7, can be upgraded on a variety of Apple iPhone models including the iPhone 4, 4S and 5. It also comes installed on the iPhone 5S and 5C. Apple does not charge for these operating system updates, but may charge fees if you decide to upgrade your iPhone to a newer model. Prices for upgrading the model of your iPhone depend on where you buy the phone and whether or not it is subsidized by the carrier.

Get the New Operating System

If you currently own an iPhone 4, 4S or 5 you can upgrade to iOS 7 free of charge directly on your iPhone or by connecting your device to iTunes and following the step-by-step process. Stay away from any websites or companies that are charging for the new update.

Future Upgrades

Apple usually only makes operating system updates available to certain iPhone, iPad and iPod models. If your iPhone is an older model, it may not be compatible with the new operating system. You'll have to upgrade to a newer iPhone model to take advantage of the latest operating system.

Get a New iPhone Model

If your iPhone is not compatible with the latest iPhone operating system, you'll have to upgrade by purchasing a new model from either a retail store, online website or your wireless carrier. As of September 2013, The iPhone 5S is available for $199 while the 5C is available for $99 with a new two-year contract with Sprint, Verizon Wireless, T-Mobile and AT&T. Older iPhone models may be cheaper or free with a contract.