diff --git a/src/emqx_reason_codes.erl b/src/emqx_reason_codes.erl
index b777b2627..f300d675d 100644
--- a/src/emqx_reason_codes.erl
+++ b/src/emqx_reason_codes.erl
@@ -126,5 +126,8 @@ compat(connack, 16#8C) -> ?CONNACK_AUTH;
 compat(connack, 16#97) -> ?CONNACK_SERVER;
 compat(connack, 16#9C) -> ?CONNACK_SERVER;
 compat(connack, 16#9D) -> ?CONNACK_SERVER;
-compat(connack, 16#9F) -> ?CONNACK_SERVER.
+compat(connack, 16#9F) -> ?CONNACK_SERVER;
+
+compat(suback, Code) when Code =< ?QOS2 -> Code;
+compat(suback, Code) when Code > 16#80  -> 16#80.