How to enable native resolution for apps on iPhone 6 and 6 Plus?

If you are using asset catalogs, go to the LaunchImages asset catalog and add the new launch images for the two new iPhones. You may need to right-click and choose "Add New Launch Image" to see a place to add the new images.

The iPhone 6 (Retina HD 4.7) requires a portrait launch image of 750 x 1334.

The iPhone 6 Plus (Retina HD 5.5) requires both portrait and landscape images sized as 1242 x 2208 and 2208 x 1242 respectively.

You can add a launch screen file that appears to work for multiple screen sizes. I just added the MainStoryboard as a launch screen file and that stopped the app from scaling. I think I will need to add a permanent launch screen later, but that got the native resolution up and working quickly. In Xcode, go to your target, general and add the launch screen file there.