Because the 1024x1024 icon size isn't actually needed by the app, I haven't included it in the build. I uploaded the build and then uploaded the icon on the app store submission page in iTunes Connect, which seems to have worked for the app store submission.
However, I'm now trying to submit for public testing via TestFlight, but when I try to create a group, I get a message complaining that I haven't uploaded a 1024x1024 icon and that I can do so via iTunes Connect. How do I do this?
If you submit an ipa generated through Xcode 9, iTunes Connect throws the below error:
Missing App Store Icon - iOS Apps must include a 1024x1024px App Store Icon in PNG
format. Without providing the icon in the Asset Catalog or via iTunes Connect, apps
cannot be submitted for App Review or Beta App Review. Refer to
https://developer.apple.com/ios/human-interface-guidelines/icons-and-images/app-icon/ for more information.
The same will be applicable only for the apps generated though Xcode 9+. If you want to avoid this, you still can generate the ipa using Xcode 8.
In Xcode 9, under App Icon section, there is a provision to add 1024*1024 icon.
Screenshot of the app icon image asset with 1024*1024 icon available here
