Facebook frequently changes its server-side code and API configurations. Even if you successfully install a version of the Facebook app that matches iOS 9.3.5 visually, certain features (like Marketplace, Reels, or Live streaming) may crash or fail to load data because Facebook's current servers no longer recognize the old app's requests.

If the App Store method fails, you will need a legacy file (specifically version 60.0 or older, which was generally the last to support iOS 9).

: If the app crashes or won't install, use Safari to visit the Facebook mobile site. You can add this to your Home Screen to act like a web app. For Advanced/Jailbroken Users

Cydia Impactor is a popular tool for installing IPA files on iOS devices. Here's how to use it:

To help narrow down the process for your specific setup, please share a few more details:

Apple transitioned its ecosystem from 32-bit architecture to 64-bit architecture with the release of iOS 11. iOS 9.3.5 is the final operating system version for older 32-bit Apple devices.

Download and install Sideloadly on your computer. Ensure iTunes is installed (on Windows) so your computer detects the iOS device hardware handlers properly. Step 2: Connect and Configure

Ensure you have the installed directly from Apple’s website (not the Microsoft Store version if you are on Windows).

If you are technically savvy and willing to take risks, you can attempt to force an IPA (iOS App Store Package) file onto your device.

Look for Facebook versions ranging between , which were optimized for legacy architectures.

Search for AppSync Unified within Cydia and install it. Restart your SpringBoard when prompted.