In addition to plenty of new products, Apple has also unveiled release dates for iOS 9, Watch OS and OS X El Capitan during its event.
In addition to two new iPhones, two new iPads and the new Apple TV, Apple has also unveiled that both iOS 9 and Watch OS will be launching on September 16th.
The iOS 9 update will be available for all iPhones since iPhone 4S, all iPot Touch models since 5th generation and all iPads since iPad 2. The Watch OS 2.0 on the other hand will come to only wearable device Apple has, the Apple Watch, and will bring plenty of new updates and improvements, including new Facebook Messenger app, the new GoPro viewfinder, 3rd party compilations and more.
The OS X El Capitan will launch on September 30th and the system requirements are not changed since OS X Yosemite, so if you can run that, you will be able to run OS X El Capitan as well.
Source:
Anandtech.com.