diff --git a/proto/src/system_messages.proto b/proto/src/system_messages.proto
index 4702734..21d0979 100644
--- a/proto/src/system_messages.proto
+++ b/proto/src/system_messages.proto
@@ -402,5 +402,7 @@
     // Package: android
     NOTE_ALL_MANAGED_SUBSCRIPTIONS_AND_MANAGED_PROFILE_OFF = 1006;
 
+    // Notify the user that audio was lowered based on Calculated Sound Dose (CSD)
+    NOTE_CSD_LOWER_AUDIO = 1007;
   }
 }