An IPA file is an iOS application archive file used to distribute and install apps on iOS devices. IPA files are essentially zip files that contain the app's binary, resources, and metadata. When you download an app from the App Store, it's actually an IPA file that's being downloaded and installed on your device. However, IPA files can also be used to install apps on iOS devices without using the App Store, which is useful for devices that are no longer supported by the App Store or for users who want to install older versions of an app.
Drag your Subway Surfers IPA file into the "Apps" library section of iTunes.
Play the version of the game that actually ran well on older hardware.
: You have downloaded a version of Subway Surfers that is too new (v1.13 or higher). Delete the IPA and source an older version, ideally v1.11 or v1.12.
: One of the last stable early versions for legacy devices. Where to Find IPA Files