diff --git a/src/protocol.cpp b/src/protocol.cpp
index ed54bf2c..090fa992 100755
--- a/src/protocol.cpp
+++ b/src/protocol.cpp
@@ -136,6 +136,7 @@ MESSAGES (with connection)
                           - 0: none, no audio coding applied
                           - 1: CELT
                           - 2: OPUS
+                          - 3: OPUS64
     - "version":         version of the audio coder, if not used this value
                          shall be set to 0
     - "audiocod arg":    argument for the audio coder, if not used this value