How do I stop the "pop" notification sound from facebook on my galaxy a5?

[mimteatr]

Not inside facebook itself but feeds updates notifications on my phone even when facebook is closed. Disabling the sound (off) in the app itself doesn't do it.

 

[mimteatr]

Well, I've renamed the "facebook.pop" file... it solved it! But if someone has a more official way to do it please do tell me