iOS 9.3.5 runs exclusively on older 32-bit processors (Apple A5, A5X, A6, and A6X chips). Apple dropped support for 32-bit apps with the release of iOS 11 in 2017. Modern IPAs are compiled strictly for 64-bit systems and will instantly crash or refuse to install on iOS 9.3.5.
This means the IPA you downloaded is either a 64-bit file or requires a higher firmware tier (like iOS 10 or 11). Double-check the library source to ensure it is verified for iOS 9 and 32-bit systems. ipa library ios 9.3.5
Older IPA files are not universal. An app built for iOS 11 or 13 (64-bit) will crash instantly on iOS 9.3.5. However, many developers stopped updating their apps in 2015-2016. The "last compatible version" of apps like Flappy Bird , Temple Run , GarageBand , Angry Birds , and Minecraft - Pocket Edition was frozen in time. An IPA library archives these "Golden Age" apps. This means the IPA you downloaded is either