diff --git a/spice/protocol.h b/spice/protocol.h
index ddfe84b..924c8cc 100644
--- a/spice/protocol.h
+++ b/spice/protocol.h
@@ -104,11 +104,13 @@ typedef struct SPICE_ATTR_PACKED SpiceSubMessageList {
 enum {
     SPICE_PLAYBACK_CAP_CELT_0_5_1,
     SPICE_PLAYBACK_CAP_VOLUME,
+    SPICE_PLAYBACK_CAP_OPUS,
 };
 
 enum {
     SPICE_RECORD_CAP_CELT_0_5_1,
     SPICE_RECORD_CAP_VOLUME,
+    SPICE_RECORD_CAP_OPUS,
 };
 
 enum {