”But that's the case with Signal et al as well isn’t it?”
No.
”Because your phone will be connecting to Signal’s servers, your cellular carrier can determine whether or not you are using the service. However, your carrier cannot gather any information about the individuals or groups with whom you are communicating.”
No.
”Because your phone will be connecting to Signal’s servers, your cellular carrier can determine whether or not you are using the service. However, your carrier cannot gather any information about the individuals or groups with whom you are communicating.”
Source: https://github.com/WhisperSystems/Signal-iOS/wiki/FAQ#what-a...