There’s an easier way (had the same issue with Spotify and iPhone 4): use the same iCloud account from the “old” device to login on a newer device. There, downl

There’s an easier way (had the same issue with Spotify and iPhone 4): use the same iCloud account from the “old” device to login on a newer device. There, download the app you want to use on the older device. Once it’s installed, go back to the older device and go to the App Store to “purchased apps”. This will now include the app you just downloaded on the newer device. Click “download”. The App Store will recognize that this app won’t run on your crappy old iOS version, but since you purchased it, it will offer you to download the latest version that still works on your device... insane, I know, but less involved than a mitm-proxy...