Jailbreaking allows you to bypass Apple's signing restrictions and use tools like AppSync Unified to install IPAs permanently. (the standard jailbreak for 32-bit iOS 9.3.5).

Do not be surprised if the app opens but refuses to let you log in.

Running iOS 9.3.5 today means you are using hardware from 2012–2015 (iPhone 4s, 5, 5c, 6, 6 Plus, or iPad equivalents). Apple no longer supports this version, and the App Store on these devices will likely show an error when you try to download modern apps like Facebook.

Note: Always scan downloaded .ipa files with VirusTotal before installing them.

Facebook will remain installed forever, notifications will work (if you grant permissions), and you will never be harassed by the 7-day clock.

You must use legacy, offline signing methods.

iOS 9.3.5 is an older version of the iOS operating system, released in 2016. Although it is no longer the latest version of iOS, some users may still be using devices that run on this version, either by choice or due to hardware limitations.