Use a tool like ipa info or open the IPA’s Info.plist (inside the Payload folder). Look for:
But if you own a device stuck on iOS 7.1.2—such as the iPhone 4, iPhone 3GS, or fourth-generation iPod touch—you’ve likely faced a harsh reality: the App Store no longer allows you to download modern apps. Worse, many older apps have been pulled or are no longer compatible. ipa files for ios 7.1.2
Within the .app bundle, several files define the app's behavior and legacy constraints: Use a tool like ipa info or open the IPA’s Info