Apple iPad 2 app help

Apple iPad 2 cannot download purchased app code of an expensive app. Is there another way around it? The app has been around for a while and it upgraded for iOS 11. The developer's website says that I can 'gift' it to myself, but the app code is for the 11 iOS compatible version. Is there any way to log-in with the Apple ID on an Mac, download the app, and then go to the App store on the iPad 2 and download the 'purchased' app from the list? Please let me know your thoughts, thanks!