The responsive iPhone and iPad simulators that debuted at WWDC this year have been (and continue to be) full of mystery and potential - quite possibly the biggest source of change in iOS 8 itself. Combined with the iPhone 6 Plus’ size, landscape mode and downscaling, there’s a lot of fluidity and responsiveness coming to iOS this year… A quick count:

  1. Ability to set explicit pixel counts in Simulator
  2. Simulator Betas “Accidentally” accepting @3x assets
  3. Ability to set size classes in addition to explicit pixel counts.
  4. Landscape mode, iPhone 6 Plus [a.k.a “Rotate to iPad”]

While the iPhone 6 Plus has been a substantial source of confusion and consternation for developers so far, this (I suspect) is nothing compared to what’s rumoured for the iPad. The substantial blurring of what constitutes and iPhone or iPad app is going to cause headaches for indies who swear by separate iPad and iPhone apps. And that’s even before you start to consider a more appropriate layout iPhone 6 Plus…

If you’re like me, after watching WWDC 2014 session 216 “Building Adaptive Apps with UIKit” you’re probably equal parts excited and nervous. Some of the cat is finally out of the bag, after a WWDC session so full of “how” and precisely no “why” - and rumours suggest more is coming. The biggest rumour for iOS on iPad so far this year has been “Split Screen” - and Size Classes (covered in aforesaid WWDC session) provide a way to offer just this.

For example: if you were able to (hypothetically) split-screen on iPad 1 with a 75/25 split, and you opened Clear in the 25%, you may consider it more appropriate to offer a different UI. Previously, if an app launched it’d simply say “Oh, I’m running on an iPad: let’s show the 1024x768pt interface.” Now, it’s a case of “I may well be running on an iPad, but the current size class I’m being run within is a compact-width, regular height view. So in this case it’s probably more appropriate to show an iPhone UI even though I’m running on an iPad”. This is a fundamental change in both how apps detect and then adjust to size changes - not to mention how apps are built and marketed.

Universal, Right?

Among independent developers, there’s a long-standing practice of separate iPhone and iPad apps. It’s understandable: you can’t price a Universal app at device “appropriate”2 points. Paid universal apps also find it tougher to climb the charts (so the wisdom goes) because purchases of a Universal app only apply towards charts on the device of purchase… So, indies go to iPhone first - and then release a second, paid, iPad app once the iPhone has established itself.

Apple, of course, has a different view. They understandably want customers who go from iPhone to iPad to have the same apps ready and waiting: they don’t want customers to have to re-discover the apps they already love and use. There’s also I believe a case of Apple believing that doing a separate app isn’t the right course because you’ve barely made a dent in getting your app onto the millions of iOS devices. By bringing out a (free) Universal update - or better still, launching Universal - you’ll get existing customers stoked about the app, helping to spread the word, and the right marketing efforts can help to drive up revenue.3

Business Aside

Whichever side of the economic fence you sit, however, there’s no denying that size classes (and possible split-screen) bring about significant potential change for separate-SKU developers. Some may simply choose to not opt-in to split-screen on iPad; some may simply ensure the iPhone app could run in split-screen conditions perhaps. Ultimately, however, these aren’t ideal solutions. Ultimately, building a Universal app with size class support ensures that no-matter what device or size class a customer places your app into, they’ll get a great experience4. Our job is make sure that happens.

Further Reading

Apple has a substantial section on Adaptive User Interfaces in the iOS 8 Design area - I’d highly recommend you check it out.


  1. I’ll leave the suggestion that is definitely happening, or ideas on how one might well enter this mythical mode to others… 

  2. iPhone at perhaps $4.99, iPad at $9.99 

  3. As you can probably guess, it would have been great to run with this with Clear… 

  4. I’m a firm believer in device-specific experiences for iOS, including (where it makes sense) iPad-only or iPhone-only apps. Not every app applies to every device, see Paper