It was a matter of time till this happened when facebook bought whatsapp.
I have moved over to telegram awhile ago, as you can be sure when facebook get there hands on anything personal it will not remain personal.
Whatsapp have already been giving access to the so called encrytption messages to the gods above.
whatsapp is anything but secure and now will be dropping adverts into your app, as most if not all whatsapp users enable the mic you cant help think the gods above love facebook. As they are buying and owning evertyhing that is personal to users.
As history has shown.... facebook and anyone associated with them will not respect your privacy.