There's an error that sliped into the documentation of the QML WebSocket Type of the newly implemented receiveBinaryMessage() signal.
The documentation states that the signal's argument is a QString, when in fact it's an ArrayBuffer - as described for the sendBinaryMessage() method.
The error can be found in the patch that implements these functionalities :
This affects the documentation and the helpers in QtCreator - which expect a string.
PS: it would certainly be interesting to give some example(s) of how to handle this binary data in QML. I myself haven't yet figured out how to use an image received that way.