expo-build-properties doesn't set iOS deployment target correctly.

[SophieJung7]

expo-build-properties doesn't set iOS deployment target correctly.

[gorbypark]

The way I understand it is that deploymentTarget is effectively the minimum SDK version you plan on supporting. On the other hand, the build SDK is determined by which version of Xcode the app is built with.

At the end of the day, you need to build with SDK17+ (which is Xcode 15.0+) but that SDK17 supports versions further back than 17. I believe RN/expo set a deploymentTarget of 13.4 as default so building with SDK17 should work all the way back to SDK13.

If you are using EAS Build to build your project, check which version of Xcode is being used. I recently upgraded a project from Expo SDK49 to Expo SDK50 and with Expo SDK49 my last build was using Xcode 14.3.1 and after upgrading to Expo SDK50 it is now using Xcode 15.2. I am not sure if there is an option somewhere to set the Xcode version? It seems tied to the Expo SDK version by default but it might be configurable somewhere.

If Xcode 15.3 is giving you the error, go to settings - locations and see which version of Xcode command line tools is being used, it should also be set to 15.3 (I guess this is actually what determines the build SDK version when building from the command line).

edit
It seems like these are the option for a build environment https://docs.expo.dev/build-reference/infrastructure/ and you would set it in app.json using something like this with the image being whatever image you want to use from the above infrastructure page.

{
  "build": {
    "production": {
      "ios": {
       "image": "macos-ventura-13.6-xcode-15.1"
    }
  }
}

[ChrisBurgdorff]

I was wondering this too. I'm not sure that the "deploymentTarget" is the same as the iOS SDK version. I have my deploymentTaget in the expo-build-properties set to 13.4, and Apple emails me telling me that our app is build with SDK version 16.4.

So we need to change the SDK version to 17.0 as per Apple, but per the expo-build-properties docs here, there doesn't seem to be an option for SDK in the Apple settings...

[Kudo]

hi there! the deployment target means the minimal supported ios version for people to install your app. that is not the same as ios sdk version for building the source code. for ios sdk version, it is related to xcode version. according to the xcode doc the minimal xcode version to support ios sdk 17 is xcode 15.0.
as @gorbypark shared, please choose an eas image that at least with xcode 15, e.g. macos-ventura-13.6-xcode-15.0.