Apple to developers: Your apps will scale on iPhone 6, iPhone 6 Plus screens

Apple's launch of the 4.7-inch iPhone 6 and 5.5-inch iPhone 6 Plus won't necessarily mean developers will have to redo their apps to make them work on the larger screens.

Phil Schiller, marketing chief of Apple, said the company's iOS 8 platform has a desktop-class scaler that allows apps to adjust to the various screen sizes. Schiller highlighted CNN's app without any code tweaks. "It just works," said Schiller.

• Read more: Apple announces iPhone 6: Better specs, new features, larger screen sizes | CNET live blog

But here's the catch. Apple's X-code allows apps to adjust to multiple screen sizes, but iPhone 6 features such as horizontal viewing and the ability to add more dense content will require some work.

It's worth noting that CNN is redoing its app to take advantage of the extra screen turf.

Given there are 1.3 million apps on iOS, there's a good chance that developers are likely to look to update their apps to take advantage of extra resolution and other features such as Reachability, which allows you to double tap TouchID and pull notifications down. That feature will allow people to work the larger iPhones with one hand.

Apple added a lot of optimization in iOS 8 for one-handed use on the bigger screens such as a predictive keyboard and recording interface.

Apple has also opened up access to its M8 chips so developers can run more graphic intensive apps closer to the processor.