Preview at WWDC likely in June, followed by September launch.
iOS 7 Adoption up to 87% Ahead of WWDC's Likely iOS 8 Announcement
Apple has traditionally seen speedy adoption of its new iOS releases because it makes it easy for customers to upgrade to the new operating system without too much trouble, and it's likely that iOS 8 will see similar adoption after its expected release this fall.
iOS 8 is expected to include upgrades to Apple's Maps app, including possible support for public transit directions and enhanced points of interest, a Healthbook app that assists users in aggregating personal health data like blood pressure, heart rate, and more -- perhaps in concert with a smart watch product -- as well as improvements to Siri and iTunes Radio, two of the more recent additions to Apple's mobile operating system.
In contrast to Apple, Google sees only 5.3% of its users running the latest version of its Android operating system, version 4.4 or KitKat, which came out in October 2013 -- a month after iOS 7 was released.
The increasing adoption rate of iOS 7 has also led to a drop in iOS 6 usage, with the older operating system now installed on just 11 percent of devices. 2 percent of devices are using older versions of iOS. In early December, iOS 7 usage was at 74 percent, jumping to 78 percent later in December, 80 percent in late January and 85 percent towards the end of March.
Apple's data, which comes directly from the App Store, represents concrete iOS 7 adoption information for developers.