This is interesting, BBC news app looks optimised for iPhone 6 display, but it's not updated, in fact last time it was updated was back in 2013, how does this work?
They built the framework for multiple sized screens in ios7 if I remember right. Unfortunately most developers did not take advantage of it so now they look dumb.
During the keynote they talked about how if developers had taken advantage of the automatic scaling that most apps would look very good on the bigger screens.