Apple's September Event: Don't Forget the Operating Systems

— -- While all eyes may be on the potential new iPhones and other hardware to be unveiled next Wednesday at Apple's special event, it's also possible users will find out when they can get their hands on hotly anticipated operating system updates.

The star of Apple's event is widely expected to be the new iPhone 6S -- but if history is any indicator, Apple fans should be able to expect some news on when they can download the public versions of three new operating system updates that were shown off at the company's Worldwide Developer's Conference in June.

Here's a quick cheat sheet about what to expect when it comes to iOS 9, OS X "El Capitan" and watchOS 2.

iOS 9

Intelligence is the driving force in iOS 9, which will include an even smarter and more proactive Siri capable of picking up context throughout your day. The digital personal assistant fields more than 1 billion requests per week, according to Apple, and will be ready for plenty more work with iOS 9.

With the new update, Siri will be able to pull up results for requests such as "Show me photos from Utah last August" and "Remind me to grab my coffee off the roof of my car when I get in."

Siri will also know to pull up music when headphones are plugged in or start an audio book a user has been listening to when they're in their car, among a slew of other context-based features.

OS X 'El Capitan'

The latest version of Apple's Mac operating system, OS X "El Capitan," has a special focus on enhancing performance for power users.

Among the new features are the ability to work across tabs in Mail, pin most visited websites in Safari and work simultaneously in windows positioned side by side. Spotlight will also be able to understand natural language, making it easier for users to find everything from files to weather and sports scores.

watchOS 2

Among the new capabilities are photo faces, including time lapses of city scenes, the ability to see a different photo every time a user glances at their wrist and nightstand mode, turning a charging watch into an alarm clock.

A time travel feature will also let users turn their crown to leap forward and backward in time to see their schedules. Siri will also respond to a voice command to start counting a workout, without a user having to touch their Apple Watch.

Many apps on the watch can run natively with the update, meaning users can expect quicker load times and even more possibilities for how they can be used.