diff --git a/zscanprotocol.hpp b/zscanprotocol.hpp
index f6398ab..59a8a30 100644
--- a/zscanprotocol.hpp
+++ b/zscanprotocol.hpp
@@ -54,6 +54,7 @@ typedef enum {
   kerr_invalid_param_num    = 3,
   kerr_subdevice_offline    = 4,
   kerr_function_not_support = 5,
+  kerr_subdevice_overtime   = 6,
 } common_ecode_t;
 }
 }  // namespace iflytop