Today someone wrote that #Signal notifies users if their contacts use the #messenger, I wondered about the explanation, because I heard something different before.
So here is the way how it really works, it got #crypto (or #hashing) and #dataprotection inherent.
https://support.signal.org/hc/en-us/articles/360007061452-Does-Signal-send-my-number-to-my-contacts-
