Determine if app is running in "scaled" mode on iPhone 6 for keyboard?

I'm trying to create a custom iOS 8 keyboard. I am using Interface Builder to arrange the keyboard layout. I have two NIB files, one for iPhone 6 and one for iPhone 5.

There are certain apps that are "scaled" up for the iPhone 6. For these apps, I want to load the iPhone 5 NIB (the iPhone 6 NIB goes off the screen).

Is there any way to determine if the current app running is running on "scaled" mode?

Unfortunately checking UIScreen mainScreen's attributes does not give me a difference between native iPhone 6 app vs scaled iPhone 6 app.