diff --git a/apps/emqx_sn/src/emqx_sn.appup.src b/apps/emqx_sn/src/emqx_sn.appup.src
index 6a4eb66d1..7b0bc91c3 100644
--- a/apps/emqx_sn/src/emqx_sn.appup.src
+++ b/apps/emqx_sn/src/emqx_sn.appup.src
@@ -1,26 +1,44 @@
 %% -*- mode: erlang -*-
 {VSN,
   [
-   {<<"4\\.3\\.[4-5]">>,[
+   {"4.3.5",[
        {load_module,emqx_sn_frame,brutal_purge,soft_purge,[]},
-       {load_module,emqx_sn_gateway,brutal_purge,soft_purge,[]}
+       {update,emqx_sn_gateway,{advance,["4.3.5"]}}
    ]},
-   {<<"4.3.[2-3]">>,[
+   {"4.3.4",[
+       {load_module,emqx_sn_frame,brutal_purge,soft_purge,[]},
+       {update,emqx_sn_gateway,{advance,["4.3.4"]}}
+   ]},
+   {"4.3.3",[
        {load_module,emqx_sn_registry,brutal_purge,soft_purge,[]},
        {load_module,emqx_sn_frame,brutal_purge,soft_purge,[]},
-       {load_module,emqx_sn_gateway,brutal_purge,soft_purge,[]}
+       {update,emqx_sn_gateway,{advance, ["4.3.3"]}}
+    ]},
+   {"4.3.2",[
+       {load_module,emqx_sn_registry,brutal_purge,soft_purge,[]},
+       {load_module,emqx_sn_frame,brutal_purge,soft_purge,[]},
+       {update,emqx_sn_gateway,{advance, ["4.3.2"]}}
     ]},
    {<<"4\\.3\\.[0-1]">>, [{restart_application,emqx_sn}]}
   ],
   [
-   {<<"4\\.3\\.[4-5]">>,[
+   {"4.3.5",[
        {load_module,emqx_sn_frame,brutal_purge,soft_purge,[]},
-       {load_module,emqx_sn_gateway,brutal_purge,soft_purge,[]}
+       {update,emqx_sn_gateway,{advance,["4.3.5"]}}
    ]},
-   {<<"4.3.[2-3]">>,[
+   {"4.3.4",[
+       {load_module,emqx_sn_frame,brutal_purge,soft_purge,[]},
+       {update,emqx_sn_gateway,{advance,["4.3.4"]}}
+   ]},
+   {"4.3.3",[
        {load_module,emqx_sn_registry,brutal_purge,soft_purge,[]},
        {load_module,emqx_sn_frame,brutal_purge,soft_purge,[]},
-       {load_module,emqx_sn_gateway,brutal_purge,soft_purge,[]}
+       {update,emqx_sn_gateway,{advance, ["4.3.3"]}}
+    ]},
+   {"4.3.2",[
+       {load_module,emqx_sn_registry,brutal_purge,soft_purge,[]},
+       {load_module,emqx_sn_frame,brutal_purge,soft_purge,[]},
+       {update,emqx_sn_gateway,{advance, ["4.3.2"]}}
     ]},
    {<<"4\\.3\\.[0-1]">>, [{restart_application,emqx_sn}]}
   ]}.
diff --git a/apps/emqx_sn/src/emqx_sn_gateway.erl b/apps/emqx_sn/src/emqx_sn_gateway.erl
index d5c574f8c..3e8c18dc9 100644
--- a/apps/emqx_sn/src/emqx_sn_gateway.erl
+++ b/apps/emqx_sn/src/emqx_sn_gateway.erl
@@ -683,8 +683,29 @@ terminate(Reason, _StateName, #state{channel  = Channel}) ->
     emqx_channel:terminate(Reason, Channel),
     ok.
 
-code_change(_Vsn, StateName, State, _Extra) ->
-    {ok, StateName, State}.
+%% in the emqx_sn:v4.3.6, we have added two new fields in the state last:
+%%  - waiting_sync_topics
+%%  - previous_outgoings_and_state
+code_change({down, _Vsn}, StateName, State, [ToVsn]) ->
+    case re:run(ToVsn, "4\\.3\\.[2-5]") of
+        {match, _} ->
+            NState0 = lists:droplast(lists:droplast(tuple_to_list(State))),
+            NState = list_to_tuple(lists:reverse(NState0)),
+            {ok, StateName, NState};
+        _ ->
+            {ok, StateName, State}
+    end;
+
+code_change(_Vsn, StateName, State, [FromVsn]) ->
+    case re:run(FromVsn, "4\\.3\\.[2-5]") of
+        {match, _} ->
+            NState = list_to_tuple(
+                       tuple_to_list(State) ++ [[], undefined]
+                      ),
+            {ok, StateName, NState};
+        _ ->
+            {ok, StateName, State}
+    end.
 
 %%--------------------------------------------------------------------
 %% Handle Call/Info