Mobile Phones iPhone & iOS iOS 9: The Basics Everything you need to know about iOS 9 by Sam Costello Writer Sam Costello has been writing about tech since 2000. His writing has appeared in publications such as CNN.com, PC World, InfoWord, and many others. our editorial process Facebook Twitter Sam Costello Updated on December 06, 2019 iOS controls apps in the background. Apple, Inc. iPhone & iOS Switching from Android Tweet Share Email Whenever Apple debuts a new version of the iOS — the operating system for the iPhone, iPad, and iPod touch — there's a mad dash to figure out if your iPhone is compatible. Even if it is, you have to decide if it makes sense to upgrade an older device since new software on old devices can be slow and buggy. When it comes to iOS 9, there are lots of new features and bug fixes. Plus, the upgrade supported more devices than in any previous release. iOS 9 Compatible Apple Devices The Apple devices that are compatible with iOS 9 are: iPhone iPod touch iPad iPhone 6S series 6th generation iPod touch iPad Pro iPhone 6 series 5th generation iPod touch iPad Air 2 iPhone SE iPad Air iPhone 5S 4th generation iPad iPhone 5C 3rd generation iPad iPhone 5 iPad 2 iPhone 4S iPad mini 4 iPad mini 3 iPad mini 2 iPad mini Key iOS 9 Features While generally well-received upon its release, some critics said iOS 9 delivered fewer major features than other versions of the iOS. This version largely focused on improving core functionality and the stability of the OS. Many observers had said that was needed after the rapid pace of changes introduced in iOS 7 and iOS 8. Among the major features introduced with iOS 9 were: Features designed to understand the user's behaviors and proactively suggest tasks and featuresSupport for the 3D Touch screen on iPhone 6S seriesNight Shift (in iOS 9.3 and up)Low-Power Mode for extended battery lifeTransit directions in Maps for selected citiesNumerous improvements to built-in appsInterface changes on the iPad, including split-screen apps and picture-in-picture support for videosPrivacy and security improvementsBetter support for older devicesPublic beta program for early access to iOS updates Later iOS 9 Releases Apple released 12 updates to iOS 9 after its debut. Every update maintained compatibility with all of the devices in the list above. Some updates added support for devices and features that hadn't been released when iOS 9.0 was released. These include iOS 9.1, which added support for the iPad Pro, Apple Pencil, and Apple TV 4, and iOS 9.3, which added Night Shift and support for multiple Apple Watches being paired to the same iPhone. For a deeper look at all versions of the iOS, check out iPhone Firmware & iOS History. What to Do If Your Device Isn't Compatible If you don't see your device on this list, it can't run iOS 9. That may be disappointing, but don't despair: iOS 8 is a good operating system. That said, if your device is so old that it's not supported here, you may want to think about upgrading. You're probably eligible for an upgrade, so shop around. You might be able to get a great deal and some slick new hardware. Just make sure to check when the next model is coming out so that you don't buy just before something new is released. iOS 9 Release History iOS 9.3.6 release: July 22, 2019iOS 9.3.5 release: Aug. 25, 2016iOS 9.3.4 release: Aug. 4, 2016iOS 9.3.3 release: July 18, 2016iOS 9.3.2 release: May 16, 2016iOS 9.3.1 release: March 31, 2016iOS 9.3 release: March 21, 2016iOS 9.2.1 release: Jan. 19, 2016iOS 9.2 release: Dec. 8, 2015iOS 9.1 release: Oct. 21, 2015iOS 9.0.2 release: Sept. 30, 2015iOS 9.0.1 release: Sept. 23, 2015iOS 9 release: Sept. 16, 2015 Apple released iOS 10 on Sept. 13, 2016. More from Lifewire Everything You Need to Know About iOS 8 The History of iOS, from Version 1.0 to 13.0 iOS 10: The Basics iOS 13: What You Need to Know iOS 11: Everything You Need to Know Where to Download Manuals for Every iPad Model Everything You Need to Know About iOS 7 The History and Evolution of the iPad Apple tvOS Versions Guide: Everything You Need to Know iOS 12: What You Need To Know How to Download the iPad Manual The History of iTunes and Its Major Versions How to Access AirDrop in the iOS Control Center Should I Upgrade My iPhone 4 to iOS 7? The History of the iPod touch What is Night Shift For iPhone And iPad?