After opening a Notification from an unrelated app (like Facebook, for instance) you can go directly back to the app by clicking the "Back to..." link at the top left of your screen. Learn how to use iOS's back button.
When multitasking (switching between apps) the app thumbnails are displayed in a stack rather than side-by-side. The core experience is the same, but the arrangement saves space. Learn how to use the new app switcher in iOS 9.
Previously, selecting multiple photos was a tedious pick-them-one-by-one process. You can grab a whole swath of photos just by sliding your finger across the screen. Learn how to select multiple photos at once.
Apple's News app, is a Flipboard-like news aggregator. It automatically builds a personalized list of content based on the sources that you choose and the articles you read. The app is even better in iOS 9.3, which adds trending news topics and curated picks. Get more details on using iOS 9's News app here.
Since the rocky start of Apple Maps three years ago, you've had to jump to a rival service (like Google Maps) to get transit directions. With iOS 9 though, your bus, train or subway (or the Tube if you prefer) has finally arrived. Learn how to get transit directions in Apple Maps here.
Choose how you'd like to see your Notifications. Recent will group notifications in a unified list. Group will let you manually define the order as you see fit. Learn how to customize your notification order.
The new Low Power setting reduces the strain on your battery when it drops below 20 percent by (among other things) suspending background app refresh. Learn how to use low-power mode in iOS 9.
Wi-Fi Assist will tell your iPhone to switch over to a cellular connection when it deems Wi-Fi connectivity to be poor. Activate it under the Cellular menu in the Settings app. Here's how and why to enable Wi-Fi Assist.
The Spotlight Search feature returns options in three categories: Siri suggestions, Nearby and News. If it's all too much you can pare down the results as you like. Learn how to customize proactive search.
If you have certain photos you'd rather not anyone else see, you can hide them from your Moments collection by selecting your photo (or photos), clicking the share icon in the bottom left corner and then the Hide button. Get more details here.
After attaching a photo to an email, you can draw on it, write text or add your signature. To get there, just press and hold on the photo and use the "markup" option.
If you miss the ALL CAPS keyboard you had before your iOS 9 upgrade, there's a toggle switch buried in Settings that will bring it back. Here's where to find it.
If you'd rather view the desktop version of a website in the Safari browser, you can jump straight there by selecting the Share button and the "Request Desktop Site" button.
Under a new dedicated Battery option in the Settings menu, you can see not only what percentage of the battery each app is using, but also how much time they've been running both on the screen and in the background.
