If you're looking to install an app on an iOS device running 7.1.2 and it's not available on the App Store anymore (since iOS 7 is quite old and many apps might not support it or be available for it), here are a few points to consider:
Some third-party services allow you to sign and install apps directly from your mobile browser. ipa files for ios 712 top
To understand the demand for IPAs compatible with iOS 7.1.2, one must understand the hardware limitations of the time. If you're looking to install an app on