Apple designers/developers used to mock Android developers over how fragmented the displays sizes are, as comparatively Apple had very few screen sizes to work with: iPad, iPhone 3.5”, and iPhone 4”. Today, Apple added in two more screen sizes, but created a much bigger design challenge.
It’s early, and we don’t know much, but the one thing that worries me is the design overhead in designing for the iPhone with these new phone sizes. Prior to today it was easy: design for the 4” display, and let iOS trim the content section of the app for the smaller display. And this works fairly well because the width of the devices was/is the same.
But that changes today.
Now we have taller and wider devices, which means the designs need to be adaptive to each device. Which requires more thought in design, more work, and more time.
These changes are likely good for everyone, except for small developers. As now the cost of entry to the App Store is higher: there’s at least three screen sizes you need to optimize for. Which is a major problem when many developers are already having trouble making money in iOS development — because now they have to spend more to make (probably) the same amount of money.
Yikes.
Allow Me More Guessing
Again I haven’t seen these phones for shit, but it would be my guess that if you are starting with an 4” UI, that will scale up to 4.7” with few issues. The only changes I would guess that need to be made are font sizing.
That 5.5” however would benefit the most from having an enhanced UI where the information display/layout is tweaked. Much like how Apple’s Weather app changed from the 3.5” version to the 4” version.
Again that’s just a wild guess on my part for now.
Cost
The point of this article is not to talk about what would need to be changed, but that your app really must be tested at these screen sizes if you want to build something truly great. And that costs a lot of money, which raises the bar a bit for making pixel perfect iOS apps.