Preview at WWDC likely in June, followed by September launch.
Apple Releases Second iOS 9.1 Public Beta
Public beta testers who already have iOS 9.1 installed can get the second beta as an over-the-air update, and those interested in getting early release software from Apple can sign up to participate in Apple's Beta Software Program.
iOS 9.1 is an update mainly designed for the iPad Pro, adding support for accessories like the Smart Keyboard and the Apple Pencil, both of which require deep integration with iOS 9. It will also include support for the new Apple TV.
The update also includes support for Unicode 8, introducing new emoji like taco, burrito, hot dog, popcorn, turkey, cheese wedge, and more, and it includes a new Siri setting that lets users give voice examples for the "Hey Siri" feature that can be activated whenever the iPhone is connected to power. With the new iPhone 6s, the new feature will be essential because "Hey Siri" can be used even when an iPhone is not plugged in.