: If you previously "purchased" Facebook on your Apple ID, go to the App Store > Purchased. Locate Facebook and tap the cloud icon. Apple may prompt you to "Download the last compatible version" .
. For legacy devices like the iPad 2 or iPhone 4S stuck on iOS 9.3.5, you must use specific workarounds to access older, compatible (iOS App Store Package) files. Methods for Installation Old iPad version 9.3.5 app download issues
By using the Phoenix jailbreak for iOS 9.3.5, users can install "AppSync Unified." This allows the installation of IPAs permanently without needing to re-sign certificates every week. Functional Limitations
