iFile is a legacy file manager for iOS that allows root-level access to the system, and while it was originally designed for jailbroken devices, it can be sideloaded as an IPA on iOS 9.3.5. Current Status & Compatibility Version Support
This is why you jailbreak. Do not search for an IPA; search for the repository. ifile ipa ios 9.3.5
Method 2: Using AltStore (Non-Jailbroken Devices) iFile is a legacy file manager for iOS
: On iOS 9, iFile is notorious for a bug where using the search function or certain file operations can cause the app to crash or, in rare cases, trigger a boot loop if system files are moved incorrectly. License Issues in rare cases
Why Do I Need iFile IPA on iOS 9.3.5?