Just two years after Apple revamped the app switching interface with iOS 7, it's changing it again. Instead of providing thumbnails of apps placed next to one another, Apple has opted to place the same thumbnails in a stack.
Double-click the home button on your iOS device to view the new interface. In the past, you would scroll from right-to-left to view previously opened apps. With iOS 9, however, the scroll direction has been reversed, requiring a gesture from left to right allowing you to scroll through apps.
Gone are profile icons of your favorite and recent contacts, which were placed above the app thumbnails in iOS 7 and iOS 8. You now access those by opening the new search interface from the home screen of your iOS device.
To force-close an app you still swipe up on the card, tossing it off into the digital void. You can also swipe multiple cards at the same time, using multiple fingers.
Another aspect of the new app switcher you'll likely notice is a change in how Handoff works. Handoff allows you to quickly open an email, message, or Safari page (just to name a few) on another Apple device without having to email it to yourself. With iOS 9, Handoff is available in the app switcher along the bottom of the screen.
When your iOS device detects content open on another Apple device that's Handoff-compatible, the small bar will show up. You can either tap or slide the bar up to the top of the screen, opening the respective app.