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

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.

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.

I've made basic black launch screens that will make the app scale properly on the iPhone 6 and iPhone 6+:

iPhone 6 Portrait

iPhone 6 Plus Portrait

If you already have a LaunchImage in your .xcassett, open it, switch to the third tab in the right menu in Xcode and tick the iOS 8.0 iPhone images to add them to the existing set. Then drag the images over:

I didn't want to introduce an asset catalog.

Per the answer from seahorseseaeo here, adding the following to info.plist worked for me. (I edited it as a "source code".) I then named the images [email protected] and [email protected]

<key>UILaunchImages</key>
<array>
    <dict>
        <key>UILaunchImageMinimumOSVersion</key>
        <string>8.0</string>
        <key>UILaunchImageName</key>
        <string>Default-667h</string>
        <key>UILaunchImageOrientation</key>
        <string>Portrait</string>
        <key>UILaunchImageSize</key>
        <string>{375, 667}</string>
    </dict>
    <dict>
        <key>UILaunchImageMinimumOSVersion</key>
        <string>8.0</string>
        <key>UILaunchImageName</key>
        <string>Default-736h</string>
        <key>UILaunchImageOrientation</key>
        <string>Portrait</string>
        <key>UILaunchImageSize</key>
        <string>{414, 736}</string>
    </dict>
</array>