On Tuesday, Apple announced that iOS 8 would be released to the public next Wednesday, September 17th. In the mean time, developers have been given the iOS 8 GM today to start playing with this is the final private release of iOS 8 before the public sees iOS 8 next week.

Apple has asked developers on Tuesday to start submitting their iOS 8-compatible applications to the iOS App Store for approval. The GM build can be used by developers to test their progress so far if everything seems to check out, developers can begin submitting their application, as the GM is about as close to the public release of iOS 8 as they're going to get.

Apple wants developers to get their applications submitted as soon as possible so that iOS 8 will be as seamless of an upgrade experience for users as possible. That way not only can users start updating their iOS devices, but they can also start updating all of their applications to take advantage of the new operating system without the unnecessary bugs and hassles.

For the most part, the user interface of iOS 8 resembles iOS 7 by a lot, but some minor user interface tweaks set the two operating systems apart. Developers also have more than 4,000 APIs to take advantage of in iOS 8, meaning that there are a lot of possibilities for upcoming application updates.

Quote Originally Posted by Apple
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.
In addition to iOS 8, developers may be asked to submit compatibility updates for Apple's latest iOS devices the iPhone 6 and the iPhone 6 Plus the iPhone 6 Plus carries an all-new retina HD 1080p screen resolution.

Sources: Apple via iMore