CODEWITHSUNDEEP
iphoneobjective-ccocoa-touch
fuzzygoat
fuzzygoat

Reputation: 26223

Upgrade iOS application to newer OS?

I am a little curious what happens in the following situation. You have an existing app on the iTunes store (with customers) that uses iOS4, you then release an update to the app that uses a newer iOS.

Upvotes: 4

Views: 174

Answers (3)

Alex Wayne
Alex Wayne

Reputation: 187024

Your "deployment target" is what matters. Setting the deployment target allows your app to set it's minimum required OS version. Many developers like to set that as far back as possible, unless your app depends on a features only available in a new iOS version.

Lets say you have an app compiled with the iOS 4 SDK and set 3.0 as the deployment target.

  • Users with iOS 3 or iOS 4 (and iOS 5) can download your app and use it.

Now you release an update compiled with the iOS 5 SDK and set 4.0 as your deployment target.

  • Users with iOS 4 or iOS 5 can download or upgrade your app and use it.
  • Users with iOS 3 that have purchased your app already cannot upgrade, but they can continue to use their existing installed version.
  • Users with iOS 3 that have not purchased your app yet will now have no way to do so.

Apple will only keep exactly one version of your app on the app store.

Upvotes: 11

Bo A
Bo A

Reputation: 3154

Usually (although not always), new OSes are the same as the previous ones but with new features. Older versions of apps often work with the latest OS but don't take advantage of the new features. The only problem users usually have is crash problems but it all depends on which APIs you use in your app.

Additionally, updates are never 'forced' upon a user - they are always optional. When it is a case that the app only works on a version of iOS which is higher than what the user has, then the update will not be offered to the user at all. They will still be able to use the older version that they have installed on their device. Apps have no expiry date.

If you want to retain compatibility for as many iOS versions as possible, you can set your iOS deployment target to the minimum OS you want your app to be compatible on. The SDK version number should not matter, but to support the latest iOS features, you would need the latest iOS SDK.

You will still have to check your APIs compatibility with the version you are targeting as a minimum OS. Look here and search for "API Diffs". Each document lists changes to the API for that iOS version. This will lists new and removed APIs as of that version. For example, UIPrintPaper, which is listed in the iOS 4.1 to 4.2 API diffs document, is a new API to iOS 4.2. So, when running on iOS 4.1 or earlier, the app will crash when calling that API. Using #if __IPHONE_OS_VERSION_MAX_ALLOWED <= __IPHONE_4_1 around your UIPrintPaper snipper will fix that problem.

Upvotes: 1

omz
omz

Reputation: 53551

Unless they download the newer version, they will of course still be able to use the old one. It's possible however that they download the update unintentionally via iTunes on the desktop. The App Store on the device itself would check if the device's OS version is compatible with the app being downloaded, but iTunes does not, so it would replace the old version in the iTunes library, leading to the app being removed from the device when the user syncs it (because the downloaded version cannot be installed).

So, for existing apps, you should keep your deployment target as low as possible and decide at runtime which additional features of a new OS version you can use. This way, you can keep compatibility with older OS versions, but still provide additional features to those who have upgraded.

Upvotes: 1

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