If the app crashes or refuses to log in (which happens as Facebook updates its servers), your best bet is the web version: Messenger.com button (the square with an up arrow) and select Request Desktop Site if it doesn't load correctly. Add to Home Screen to create a shortcut icon that looks just like an app. A Note on Performance
Are you getting a specific when you try to download? download messenger for ipad ios 9.3.5
Yes. Facebook regularly deprecates older API versions. You might get a “Version no longer supported” message in the future. When that happens, only the Safari method will remain. If the app crashes or refuses to log
Just in case.