The latest iteration of Apple’s operating system is finally here, just a few short days before the iPhone 6 itself—both versions—makes its actual appearance.

Developers have had access to iOS 8 since June so they could explore new features, test their apps, and see what’s changed. If you’re just catching up now, here are some of the biggest changes you’ll encounter as a developer when you start working with iOS 8.

Adaptive User Interface

It’s time to start thinking differently about user interfaces.

In iOS 7 and previous versions, developers needed to consider different ways users might encounter their apps—primarily the landscape (horizontal) and portrait (vertical) views. The introduction of Auto Layout, a tool to simplify the process of fitting apps to screens, in Apple’s developer suite Xcode minimized that particular headache.

See also: Hold Up! Here’s Why You Might Want To Postpone That iOS 8 Upgrade

Now, says Step Christopher, iOS team manager and instructor at Big Nerd Ranch, Apple wants to change the way developers think about designing apps completely. “Apple no longer wants us to be thinking of specific screen modes, he said during a demo. “Instead they want us to target general sizes and let them flow out to the different devices and orientation as appropriate.”

Christopher thinks this means that soon Auto Layout may be the only, or at least most way to design apps for Apple products. “If you’re not using Auto Layout it’s something you need to get up to speed on very quickly,” he said.

Context Sensitivity

Today’s Apple users increasingly want smarter devices. That includes day modes and night modes for apps that adjust their brightness according to the time.

Users may also notice that more apps want to access the phone’s location data. That’s already becoming a bigger thing, but as iOS 8 makes it an easier feature for developers to include, it’ll become even more popular.

iOS 8’s new capabilities allow for context sensitivity in regard to motion, too. Since the latest Apple devices have sensors to detect altitude and movement, those sensors are now fair game for app development. New apps, or apps converted for iOS 8 could potentially deliver different displays to users who are walking than to those who are driving.

Extended Functionality

Apple didn’t just release 4,000 new APIs for developers. In iOS 8, it also made it easier to add API functionality to apps in general.

See also: How To Download And Install Apple’s iOS 8 Beta

APIs allow developers to add new functionality to their apps without reinventing the wheel. However, testing the new apps has been challenging so far because developers are only able to see how they’ll look using the new software, not hardware.

Now that Apple has finally released new phones, testing how APIs work on the latest phones running iOS 8 will be a little less frustrating.

Outside The Box

The Notification Center is going to play a much larger role with apps in iOS 8. More developers may want to take advantage of the ability to display new kinds of notifications from different apps.

Some developers are even referring to one kind of new notification, which Apple calls “Today Extensions,” as “widgets” since they bring some of an app’s functionality outside the app proper.

Zach Waldowski, a software developer at Big Nerd Ranch, demonstrated that adding extensions to app functionality is as simple as opening up Xcode, clicking “Application Extension” and adding it to your app.

Swift

No discussion of iOS 8 is complete without a mention of Apple’s new in-house development language, Swift.

Introduced at the World Wide Developer’s Conference, the language is designed to be simpler to use than Objective-C, while still being compatible with Objective-C. Apple hopes an easy-to-use language will encourage more developers to build on iOS 8.

See also: Apple’s Swift Language Goes Pro, Reaches Version 1.0

Swift just got upgraded to version 1.0, which means it’s officially out of beta. Apps that include some—or more—Swift coding are now allowed in the app store. That gives more developers an incentive to try it out for new apps right as the new devices are coming out.

Photo by Global Panorama