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Comment by kevingadd | Hacker News Reader

Doesn't requiring the new build pipeline plus 'optimized for iOS 7', mean you can't support most older iOS devices anymore? I know that is how the build pipeline stuff worked for desktop OS X apps - they tended to deprecate the ability to build for older OS versions when you installed the latest rev of XCode.

If so, how far back does it go? Like, if I compile an iOS7 optimized app, will it work on iOS6 devices? What about iOS5? Do they schedule the support deprecation based on lifetime (i.e. all devices released in last 2yrs will work) or is it just based on software versions?

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iOS apps in Xcode have a "Base SDK" (which is the actual SDK you're building against: must be iOS 7.0 from Feb 1). But you then also set a "deployment target", which is effectively the oldest version of iOS you still want to support. Set this to iOS 6, for example, and you'll be supporting both versions, even after Feb 1.

One of course needs to be careful about using new APIs/features in this situation (detect whether a certain method/selector exists before using it, for instance) – as we don't want to throw runtime errors on the older OS.

http://stackoverflow.com/questions/1358033/iphone-base-versu...

http://stackoverflow.com/questions/986589/how-do-you-optiona...

There's an OS X app I found not too long ago that helps immensely with checking the deployment target against the actual APIs used in order to make sure you correctly avoid unavailable stuff: http://www.deploymateapp.com

No, you can build against the iOS 7 SDK and still support older versions of iOS. With Xcode 5 you can only build against iOS 7. You can also have entirely separate functionality for different OS versions in the same app bundle.

I've never tried it, but as far as I'm ware, you could theoretically build agains iOS 7 and have the app run on iOS 2.0, assuming the App Store still works.

Deployment targets earlier than 4.3 require armv6 libraries to support all devices, which Apple no longer ships. One can build an armv6 slice using an older toolchain and lipo it with armv7/armv7s slices built against 7.0, but it's not clear if Apple will accept such binaries as App Store submissions.

I currently have an app in the store that has been optimized for iOS 7 but works as far back as iOS 5.1. You could probably support earlier versions as long as you verify the OS supports a feature/method before calling it.

Users can now install older versions that are compatible, but you can't update them anymore once you go past that point.

Any sources for that? I stil haven't fount any info if you can update old versions of your app

Just experience. If you try and download an iOS7-only app on iOS6 you get an option to download a previous version.

It's been announced a while back, for example here https://developer.apple.com/news/?id=9182013a

"Previous versions of your apps are now available for re‑download by users who have already purchased them, allowing customers to use your apps with older devices which may no longer be supported by the current version of your app. If you do not wish to make these versions available, you can manage the availability of your apps' previous versions in the Rights and Pricing section of the Manage Your Apps module in iTunes Connect."

My copy of Xcode 5 supports Mac OS X deployment targets back to 10.4. Presumably the only reason it doesn't go any farther than that is because nothing prior to 10.4 ran on Intel, and Xcode doesn't ship PowerPC compilers these days.

On the iOS side, my copy of Xcode 5 supports deployment targets back to iOS 4.3. I think that may be similar to the reason for stopping at 10.4, but with ARMv6/7 instead of PowerPC/Intel.

The hard part is finding a device that can run 4.3 for testing. Technically, you could launch an app that supports iOS 2 or 3 all the way to iOS 7, the hardship is testing! Unlike Android post-Froyo, Apple's emulators have never been that accurate. in both cases, memory and device limits on older hardware become the significant bottlenecks.

That and with every OS X update you lose another simulator major version each year. Typing from memory, so I could be wrong: 10.6 had everything. 10.7 lost 3.x, 10.8 lost 4.x and 10.9 lost 5.x simulation. I had to install VMs to run emulators, how sad is that?

All this would be fine if Apple allowed developers to downgrade as post-Xcode 5 hinted, an option removed when the jail breaking started.

When did Apple hint at being able to downgrade devices?

In Xcode. http://wiki.canby.k12.or.us/groups/ipodusergroup/wiki/a507f/...

Until recently, Xcode always offered a (non-functional since iOS 4 or so) way to downgrade your device.

Now, they didn't document it as such, but why else would you make a menu that shows only past versions of an OS and let's you "Restore" such a release? ;-)

I'm also interested in the answer to this. Building for Android allows you to target a wide range of versions even if your build target is the latest; is there any analogue to this in the iOS world?

You can build for ios 7 at the same time as ios 6. They tend to assume you'll only want to target the latest, but it can be done without much trouble, esp. if you already have a tested older project and are willing to put more time in to testing. I'm supporting an app which supports ios 5-7 at present but we tend to test only on 6-7, and have changed some of the UI to match better with ios7.

The issues tend to be with matching chrome if you have custom controls, but if you don't have many custom controls, you'd probably be fine. I imagine it's not very different from the story for Android.

You can use:

if ([object respondsToSelector:@selector(selectorYoureCalling:)]) { //it Does! }

To check if the iOS version your app is installed on has the method and then use it if it does. It's pretty easy to keep things backwards compatible as long as you add fallbacks for functionality that's not present it older versions.

You can do it in iOS world too. But the iOS7 is little different. I recently updated my app with iOS7 support. Many places in the code I had to write something like

if(version >= 7) {

  // some code which only works on iOS7
  // or some workaround for iOS7

} else {

  // code which works in older version

}

Previously I never had to write such code to support iOS6 and iOS5 together.

But the situation is much better than Android world. I also have the Android version of the same app (http://www.avabodh.com/lekh)and I have to write lot of version specific if-else in the code.

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