It's Christmas Eve for fans of Apple Inc. (NASDAQ:AAPL), as we're just one day away from the opening of the 2013 Worldwide Developers Conference, which runs through Friday. The Cupertino, Calif.-based iPhone maker is expected to announce a slew of hardware and software upgrades to its lineup, but chief among them is iOS 7 (internally named "Innsbruck"), which is said to introduce sweeping visual and functional changes to the mobile operating system for the iPhone, iPad and iPod touch.

Apple is said to have overhauled the design in iOS 7, which would be the first major redesign since 2007 when the very first iOS launched inside the original iPhone. Courtesy /

With Apple's lead design guru Jonathan "Jony" Ive taking the helm for iOS for the first time this year -- as well as all "human interface" duties at Apple, a move made after the company parted ways with with its longtime iOS director Scott Forstall in October -- iOS 7 is said to be a very different experience from all past iOS releases, and the first major redesign since the very first iOS launched in 2007 inside the original iPhone.

What can users expect from the completely revamped iOS 7? After months upon months of rumors, we've narrowed down the most likely features of iOS 7. Here's what we came up with:

1. Flatter Colors

While only some of the app icons in iOS 7 will reportedly see complete overhauls, most of the icons and imagery in iOS 7 won't be redesigned, just simplified. Ive has said he's not a fan of the many skeuomorphic elements in the current iOS -- those ornamental elements that serve only as decorating metaphors instead of functional features -- and the current icons in iOS 6 essentially fake light cues to create artificial shine or shadow on the app icons. In iOS 7, expect Apple to remove gloss in favor of bolder colors, much like the flat colors and shapes in Microsoft's metro interface for Windows 8 and Windows Phone.

Graphic designer Surenix shows the difference between an app icon in iOS 6 to the new, flatter design in iOS 7. Courtesy / Surenix

2. A Sweeping Removal of Visual Metaphors

According to many Apple insiders, Steve Jobs was always a fan of skeuomorphism, or the use of visual metaphors to help make applications and features feel more familiar to users. For instance, the yellow lined Notepad app feels like a notepad, the wood-finished Newsstand feels like a news stand, and the green felt textures in Game Center make it feel like a card table. But while Jobs enjoyed these skeuomorphic elements, many designers in and out of Apple criticized these design elements, calling them essentially useless and amateurish.

Graphic designer Surenix was able to recreate some of the icons shown from the blurry photo taken by Sonny Dickson, which shows how the colors in iOS 7 are much flatter and lack the reflection effect. Courtesy / Surenix

Luckily for those long-dissatisfied designers, Ive was never a huge fan of the skeuomorphic features in iOS, so get ready for a much simplified, much cleaner experience in iOS 7, especially in Apple's first-party apps like iBooks and others.

3. More Lock Screen and Home Screen Options

The iOS lock screen badly needs a facelift in iOS 7. Over the past several years, Apple's rivals at Google and Microsoft have given users more ways to customize their home screens, letting them choose static photos or animated images. On the current iOS lock screen, users see a simple photo with the date, time and “Slide to Unlock.” Apple doesn’t need to get too fancy here, but many believe Apple will finally give into fans with options for the lock screen background, as well as more shortcuts to important iOS 7 features, including screen brightness, Wi-Fi, 3G/4G, Bluetooth, Mute, Airplane Mode, Personal Hotspot, and more. The popular jailbreaking app Auxo has many of these features, and users seem to love them.

Auxo, the enhanced multitasking tray for jailbroken iOS devices, is now available to purchase through Cydia. Courtesy/

4. Even More App Interconnectivity

In iOS 5 and iOS 6, Apple gave users the chance to share their moments, photos and achievements with the world by immediately being able to tweet or post to Facebook from anywhere in iOS. But besides being able to share to Facebook, Twitter, Photo Stream and Mail, iOS leaves much to be desired in terms of sharing. In iOS 7, Apple is reportedly giving customers even more options to upload their new videos directly to Vimeo (sorry YouTube, but you're a Google property), and share files and folders to cloud-based apps like Dropbox.

5. Major Improvements to Siri's AI

Even though it's been less than two years since Siri popularized the virtual personal assistant in 2011, Apple's competitors, particularly Google, have eclipsed the Siri in both speed and functionality. When Google added the voice function to its Search app in iOS last year, Google’s downloadable third-party app became effectively faster, smarter, more accurate and more helpful than Apple’s baked-in software, which has proved something of an embarrassment for the engineers in Cupertino.

Siri definitely needs improvements to its overall speed -- taking a page from the features in Google Voice Search would be a start, such as displaying the spoken text as it's said or quickly reading aloud answers from Wikipedia or the Web. But as Apple CEO Tim Cook discussed at the D10 Conference in 2012, Apple engineers are working on making Siri's AI more human, and to do that, they want to give her the power of context.

If Apple gives Siri a contextual brain in iOS 7, she could easily catch up to Google Voice Search. If Siri could discern its owner’s voice and also remember past questions and preferences, Siri could truly become a personal assistant. With advanced AI that could remember what allergies a user has, or what restaurants a person has visited, Siri in iOS 7 could have unlimited potential, especially in the medical industry. Most sick people don’t need a doctor, just medical advice. If Siri can take answers from WebMD or the Internet in iOS 7, users could save themselves a great deal of time and money. Or, better yet, if the user truly doesn't feel well, Siri could essentially follow a conversation tree -- the same rundown every doctor gives before a full check-up, asking about current conditions while cross-referencing the new information with past conditions or maladies -- Siri in iOS 7 could save doctors a lot of time if they could quickly and easily get an accurate medical history from the user's personal assistant.

If Siri can listen to its user and ask unique questions based on responses, Siri could become a much more powerful assistant, rather than just a helper every now and then. With better integration to the Web, Wikipedia, and even other apps like iTunes and CNN, Siri could be the equivalent of a doctor, a DJ, a journalist, and much, much more. For more on what we hope Siri can do in iOS 7, check out the 9 features we hope Apple gives Siri in iOS 7.

What do you think of these likely iOS 7 features? What features would you like to see Apple introduce to the iOS ecosystem for iPhone and iPad? What are your least favorite features in the current iOS? Sound off in the comments section below.

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