Apple's iOS 7 was released today and made available for download. Earlier today, the download was not available, but, as of now, the iOS 7 is available. Users can download the upgrade either through iTunes or by going to Software Update, under their phone's Settings menu.

iOS 7 is compatible with iPhone 4, iPhone 4S, iPhone5, and the upcoming iPhone 5S and iPhone 5C. Users will also be able to download iOS 7 on their iPad 2, iPad with Retina and iPad Mini.

iOS 7 is the biggest change to Apple's mobile operating system since the introduction of the iPhone, according to Tim Cook, Apple's CEO, during Apple's Worldwide Developers Conference in June.

The biggest new features of the iOS 7 include the AirDrop and Control Center.

With AirDrop, Apple becomes more on par with some of its competitors. AirDrop allows users to share items like videos, contacts and photos from any app with a Share button. AirDrop then sends the item via Wi-Fi or Bluetooth through a secure network.

The Control Center will give users easy access to commonly used apps and commands such as Airplane mode, brightness display , Wi-Fi control, Bluetooth, Do Not Disturb, Lock screen orientation and music control. All that is needed is a quick swipe to access tools like iOS 7's new flashlight, as well customer favorites like the calculator, camera and timer.

The Notification Center will also be upgraded. Typically, the Notification Centers shows users their new mail, to-do list, missed calls and similar news. iOS 7 adds a feature called "Today." With Today, the iPhone will display all of the news of the day including weather, traffic, and birthdays. As usual, the Notification Center will be accessible from any screen by swiping down. With iOS 7, the Notification Center will also be accessible through the Lock screen.

No major upgrade is complete without a makeover. The new iOS will have a "flatter" design. Apps like Notes and Weather are re-designed. Changes in iOS 7 include adjustments to the size and shape of app icons and other commonly used items, as well as differences in iconography and typography. The app icons for iOS 7 will now feature a "superellipse" shape.

Apple has also made iOS 7 refresh popular apps according to the user's tendencies. For example, if a user usually checks his or her Facebook app at 12 p.m. daily, then iOS 7 will refresh the app for the user at that time when his or her phone is in a low-power mode (such as when it is on and connected to Wi-Fi.)

In addition, Apple's app store will show shoppers "Apps Near Me," which are apps popular in the user's area. Downloaded apps will also update themselves automatically.

There is also a new iTunes Radio. Siri will be re-vamped in iOS 7 to include Wikipedia and Twitter in its searches. iOS 7 will have improved, more distinct ringtones available as well.