diff --git a/headers/private/app/RegistrarDefs.h b/headers/private/app/RegistrarDefs.h
index 4868f91fb9..e3b1ddd8d1 100644
--- a/headers/private/app/RegistrarDefs.h
+++ b/headers/private/app/RegistrarDefs.h
@@ -76,6 +76,8 @@ enum {
 	B_REG_UNREGISTER_MESSAGE_RUNNER			= 'rgru',
 	B_REG_SET_MESSAGE_RUNNER_PARAMS			= 'rgrx',
 	B_REG_GET_MESSAGE_RUNNER_INFO			= 'rgri',
+	// internal registrar messages
+	B_REG_ROSTER_SANITY_EVENT				= 'rgir',
 };
 
 // B_REG_MIME_SET_PARAM "which" constants