If you have downloaded Facebook in the past using your Apple ID, it will appear here. The Cloud Icon: Tap the cloud icon to download. Confirm the Legacy Version: iOS will prompt you with: "Do you want to download the last compatible version?"
This paper explores the technical constraints, security implications, and installation methodologies for running Facebook on iOS 9.3.5. As of 2026, iOS 9.3.5 (the final release for devices like the iPad 2 and iPhone 4S) exists in a "legacy" state where the official App Store version of Facebook is no longer compatible. The Legacy Dilemma: Why an IPA?
The "best" way to get Facebook on older firmware is through the App Store's "Last Compatible Version" feature rather than risky third-party files from untrusted sites. The "Purchased" Tab Method Log into your iCloud/App Store account