iOS 8: The Basics

With the introduction of iOS 8, Apple introduced hundreds of great new features like Handoff and iCloud Drive, improvements to the iOS's user interface, and new built-in apps like Health. 

Another major, positive change from earlier versions of the OS had to do with device support. In the past, when a new version of the iOS was released, some older iPhone, iPad, and iPod touch models were unable to use certain advanced features available in that version of the iOS. That was not true with iOS 8. Any device that could run iOS 8 could use all of its features.

Apple released 10 updates to iOS 8. All of those releases continued to be compatible with all devices in the table above. 

For an overview of and details on the iOS's full release history, check out iPhone Firmware & iOS History.

The iOS 8.0.1 update was notable because Apple withdrew it the day it was released. This about-face came after reports that the update caused problems in the 4G cellular connection and Touch ID fingerprint scanner features of the then-recently released iPhone 6 series models. Apple released iOS 8.0.2, which delivered the same improved features as 8.0.1 and fixed the bugs, the next day.

After the major interface and feature overhauls introduced in iOS 7, iOS 8 wasn't quite as dramatic a change. It used basically the same interface, but also delivered some core changes to the OS and some valuable improvements to the apps that came pre-installed on it. Notable iOS 8 features include:

• Handoff to swap data and tasks between iOS devices and Macs.
• Third-party keyboards.
• Health app and HealthKit framework.
• App extensions for sharing features between apps.
• Family Sharing of iTunes and App Store purchases.
• iCloud Drive.
• Touch ID support in third-party apps.
• HomeKit for smart home/Internet of Things support.
• Redesigned Notification Center.
• Sending audio clips in iMessage.
• AirDrop from iOS devices to Macs.

If your device isn't on this list, it can't run iOS 8 (in some cases — such as the iPhone 6S series or newer — that's because it can only run newer versions). That isn't entirely bad news. Having the latest and greatest features is preferable, but many devices not on this list can run iOS 7, which is a very good operating system in its own right (see the full list of iOS 7-compatible devices).

If your device can't run iOS 8, it might be time to consider upgrading to a new phone. Not only will be able to run the latest OS, but you'll also benefit from a ton of valuable new hardware features like a faster processor, longer battery life, and an improved camera.

• iOS 8.4.1 release: Aug. 13, 2015
• iOS 8.4 release: June 30, 2015
• iOS 8.3 release: April 8, 2015
• iOS 8.2 release: March 2, 2015
• iOS 8.1.3 release: Jan. 27, 2015
• iOS 8.1.2 release: Dec. 9, 2014
• iOS 8.1.1 release: Nov. 17, 2014
• iOS 8.1 release: Oct. 20, 2014
• iOS 8.0.2 release: Sept. 25, 2014
• iOS 8.0.1 release: Sept. 24, 2014 (withdrawn due to bugs)
• iOS 8 release: Sept. 17, 2014

iOS 9 was released Sept. 16, 2015.