diff --git a/proto/src/system_messages.proto b/proto/src/system_messages.proto
index e8db80a..994bdb5 100644
--- a/proto/src/system_messages.proto
+++ b/proto/src/system_messages.proto
@@ -314,6 +314,10 @@
     // Package: com.android.systemui
     NOTE_ADAPTIVE_NOTIFICATIONS = 76;
 
+    // Warn the user that the device's Headless System User Mode status doesn't match the build's.
+    // Package: android
+    NOTE_WRONG_HSUM_STATUS = 77;
+
     // ADD_NEW_IDS_ABOVE_THIS_LINE
     // Legacy IDs with arbitrary values appear below
     // Legacy IDs existed as stable non-conflicting constants prior to the O release