6-hours ago, I received an email from Apple Developer Center that iOS8 Apps can now be submitted. Good news is Swift is now final! Quote from their email:
Make sure your apps take advantage of all the great new features in iOS 8, which will soon be available to hundreds of millions of customers around the world.
To prepare your apps for the App Store, download and build with the iOS 8 and Xcode 6 GM seeds from the iOS Dev Center. With these latest seeds, Swift is now final and you can submit your iOS apps written with Swift to the App Store.
In addition, you can now invite your internal team members to test pre-release versions of your iOS 8 apps with TestFlight Beta Testing. You can also submit App Bundles to the App Store to provide up to 10 of your apps in a single purchase at a reduced price. And be sure to learn about creating compelling App Previews to help customers better understand your app and encourage more downloads.
Adaptive applications for different sizes of iOS devices is the key to make development of apps easy. Need to take advantage on this one.