IOS version and retina support - ios

What is the cut off for iOS version where I can say everything is Retina Display and I don't need to worry about the 1x images anymore? I want to say anything iOS 8 or newer is going to be Retina Display, but does it goes back further?

If your app is iPhone only, then iOS 7.
However for universal apps, iPad 2 and mini are still supported even by iOS 9.

Related

If an app is only for iPhone, where does the iPad pull it's 1x/2x version from?

Does it use the iPhone 6 Plus version? Where does it get it from?
I ask because I have been building my app based on screen dimensions. iPad's have different screen dimension ratios so I decided to make my app iPhone only. However, when I run my app on an iPad the positioning of everything is totally screwed up! But when I run it on every other iPhone device (from 5 to 6s plus because iPhone 4 dimensions are off) it looks fine!
So where does it get it's version from? Does it pull from the iPhone 4?
Every app can run on the iPad no matter if it is supported or not. If the app is NOT built for iPad (iPhone only) - it would show up as it shows up on an iPhone 4. Be sure that your screens support iPhone 4 or you won't make it past the app review process (annoying but true).
From the Apple iOS App Store Review Guidelines (https://developer.apple.com/app-store/review/guidelines/):
2.10 iPhone Apps must also run on iPad without modification, at iPhone resolution, and at 2X iPhone 3GS resolution

Testing #1x view in simulator

Is it still possible to test an #1x view app in simulator, since most iOS devices doesn't support it. Also, I believe that no device will be supported with iOS 10.
The iPad 2 simulators are still available (at least for iOS 9.3).
They have a non retina resolution, so you can use them to run your app in a #1x environment. Even if your app is an iPhone app you can still use them to simulate an #1x iPhone (if your app is iPhone only).
iOS 10 will support the iPad 2 and iPad mini, the two remaining devices which support #1x images (see the Icon and Image Sizes section of the HIG).
With a fresh install of Xcode 8 Beta and iOS 10 beta for these devices I was able to test #1x images.

How do I make my app scale properly on 13-inch iOS tablets?

We finally got a 12.9-inch iPad Pro in the office! However, when putting our app on it, it's just stretched to fit the screen. Looking at the project file, I don't see any settings that would change this. How do I make our app properly scale on these large iPads?
I already tried Googling this, but I keep getting reviews and people begging for Xcode on iOS:
How do i make my app work on iPad Pro?
Make Xcode project iPad Pro compatible
iPad Pro .xcodeproj
Making your app work in iPad Pro
How to optimize app for iPad Pro
etc.
If you build with the iOS 9 SDK, then your app is expected to support all resolutions. Same if you use iOS 8 SDK and use a launch storyboard. Without that, iOS assumes that you don't support the resolution, but scales an iPad app. So that's what you need to do: iOS 9 SDK, and/or launch storyboard.

App on appstore has iPad support when iPhone family set?

I have an app on the App Store and I've made sure several times that iPhone is selected in: App > Target > General > Deployment Info > Devices > iPhone
..rather than Universal or iPad.
It appears every time the app is approved it still says iPad supported, how can I disable iPad support completely since the above "solution" doesn't work?
That is normal, iPhone applications can also run on iPad in a iPhone simulator mode.
This is the description of one application of mine only available for iPhone.
Compatibility: Requires iOS 7.0 or later. Compatible with iPhone,
iPad, and iPod touch. This app is optimized for iPhone 5.
This one just for iPad:
Compatibility: Requires iOS 7.0 or later. Compatible with iPad.
and this Universal (both iphone and ipad, no simulator)
Compatibility: Requires iOS 7.0 or later. Compatible with iPhone,
iPad, and iPod touch. This app is optimized for iPhone 5.
It seems the same, but in the reality there is also a + sign with written:
This app is designed for both iPhone and iPad
Making them "Just for iPhone" doesn't let iPads not use them. Imagine this bit of a crisis: on the first iPad's release, how did apps get on the store, since they were designed for iPhone? Developers had some options:
Make an "HD" or "iPad" version. This involved redoing the entire UI so it would fit on the bigger screen.
Do nothing. The iPad's would get the iPhone version of the app, but they would just be, as you can guess, oversized iPhone apps.
After a couple years, there was another option:
Make a "universal" app. This allowed both UI's, both big and small, retina and 1x scale devices, to be "bundled" together in the same Bundle. (heh, bundle pun.) Puns aside, this allowed for apps like "Facebook" to run on iPad, iPhone 3GS, iPhone 4, iPhone 5, iPhone 6, the future iPhone cheeseburger double-decker 7+, and everything else, without having to remake the entire app.
On the iPad, as mentioned by Andrea, it runs in an "iPhone Simulator" mode. This makes the tiny screen be rendered in the tiny screen scale, and, since iPad is over twice the size of the iPhone, it gave the iPad a "2x" button to zoom it in and make the UI bigger.
It's like an app designed for iPhone 4 running on an iPhone 6 Plus.
The iPhone 4 renders stuff at 960x720 landscape or 720x960 portrait, and iPhone 6 Plus's display is much bigger. To accommodate, it letterboxes the content and scales it up automatically.

Which iPhone app version do I see on my iPad?

I have an iPhone app which has been coded to be optimised for the various iPhone screen dimensions and resolutions. I have not included an iPad version.
When I view this app on an iPad Air 2, which version will I be seeing? The version optimised for an iPhone 6 Plus? Or something else?
(My reason for asking this question is that I don't have an iPhone 6 or 6 Plus to test on so I'm wondering if my iPad can do the job for me. I'm mainly interested in seeing the layout and image resolutions).

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