Now we know: iOS7 represents, according to Cook, the biggest software update ever. From a different aesthetic to a new multitasking system, the changes are many. That Ive and team went in a different direction with iOS7's looks should come as little surprise to those who know Ive or follow Apple (AAPL) closely. Ive was reportedly not a fan of "skeuomorphism," the design philosophy that led to digital representations of real-world items, like the reel-to-reel tape deck previously found in Apple's podcast app. After six years, most users should be pretty familiar with how iOS works without such visual cues.

Here's a look at many of the new features users will discover this fall.

iOS, but flatter

When iOS7 becomes widely available this fall, users will quickly notice that any sort of nostalgic visual cues have been done away with. This operating system is flatter, bolder, and more translucent. For the most part, app and text look more two-dimensional, and a more striking color palette permeates every screen. Semi-transparent menu layers, like those seen in the new Control Center, lend an updated, hipper look.

Real multitasking

Multitasking for iOS users, or the ability to have several apps running at once, was a distinctly Apple experience. Switching from app to app was quick, but many third-party apps couldn't update with new information in the background, something Apple mostly disallowed in favor of battery life. A new multitasking screen treats many open apps as larger panes to swipe through.

A way better Siri

You'll notice something different about Apple's spunky digital assistant, and we're not just talking about a new coat of paint, or the fact that Siri sounds more natural with an updated male or female voice. Apple promises faster answers to questions, more sources for Siri to dig through, and the ability to ask it to return calls, play voicemail, and control iTunes Radio.

Better battery life

Just like OSX Mavericks, iOS7 was designed from the ground up to conserve battery life where possible. As just one example, the new multitasking ability helps apps figure out whether or not users have a good mobile or WiFi Internet connection. Depending on signal strength, apps will fetch data -- drawing energy from the battery in the process -- or hold off.

Mission control

The new Control Center offers users many of the virtual buttons required to adjust screen brightness, turn WiFi and Bluetooth on and off, change music tracks, and access shortcuts to their camera, calculator, timer, and flashlight.

Smarter notifications

For those who use their iPhones for work and play -- and let's face it, there are more and more of them -- the new Notifications Center covers the basics but also organizes that information into more useful sections. A new feature called "Today" serves up a summary of today's weather, appointments, missed calls, and other information in one screen.

One camera, many filters

The Camera app still offers the ability to shoot standard stills, panoramas, and videos, but now there's a "square"-shaped photo feature and at least nine built-in filters that render shots in black and white, cool down the contrast, or dial up the sepia for a vintage-retro look.

Improved photos

iOS users don't have to scroll through countless photos to get at what they want anymore. Based on factors like time and place, Apple can organize shots into what it calls "moments," or events, that are housed in "collections," or albums, that show up under "years." (It's a lot simpler than it sounds. Trust us.)

Dropping off

AirDrop for iOS works as you might expect, provided there's WiFi and Bluetooth around. Nearby users can quickly -- and securely -- share photos, videos, contacts, and anything else by pressing the "Share" button in an app.

Scroll master

Safari for iOS has received some nips and tucks, namely new flat buttons that stay hidden until users scroll so they can see more of a web page at once. The Reading List follows the same philosophy to its OS X Mavericks counterpart: Going from one story to another means simply scrolling down.

Radio

Apple's oft-rumored music streaming service has arrived. With hundreds of featured and user-customizable stations, listeners can jam on any contemporary Apple device. iTunes Radio is ad-supported, meaning most listeners will hear the occasional commercial, but iTunes Match subscribers will experience their streamed music ad-free.