iOS simulator (iPhone6) viewControllers does not match storyBoard controllers

in another project of mine, which I started working on a few months ago, if I take some storyboard viewController and add it some pink view for instance, the pink view will appear exactly as in the storyboard when running in iOS simulator iPhone 6. while in a new project I'm working on, the view in iOS simulator (iPhone 6) is in size of the storyboard view (which is iPhone 5).

btw, in my previous project i didn't use size Classes, and didn't have any constrains anywhere. I'd like it to stay like this in my current project. how can it be done ? thanks in advance!