Launch Sideloadly. It should automatically detect your connected iPad or iPhone.
: Enter your Apple ID email address (this is required to sign the app locally).
Before we proceed, it's essential to address the elephant in the room. Installing an IPA file can pose some risks to your device, especially if you're not careful. However, if you follow the steps outlined in this article, and use a trusted source for the IPA file, the risks are minimal.
Open the App Store on your old iPad or iPhone.
: This method relies on Apple's servers still hosting that specific old IPA file. For reasons stated above, these are now almost certainly gone.