如何禁用iPhone 6的本机分辨率?

I have several games made with Cocos2d-iphone. All of them are old projects created with Xcode 4 or 5. All games scale fine on the new iPhone 6 and 6 Plus except one that seems to avoid the scaling mode and is running on native iPhone 6/6 Plus resolution. The project does not contain Launch images with the resolutions that seem to disable the scaling mode as explained I have several games made with Cocos2d-iphone.