diff --git a/lib-ce/emqx_modules/src/emqx_mod_delayed.erl b/lib-ce/emqx_modules/src/emqx_mod_delayed.erl
index ac5be58b2..53280becc 100644
--- a/lib-ce/emqx_modules/src/emqx_mod_delayed.erl
+++ b/lib-ce/emqx_modules/src/emqx_mod_delayed.erl
@@ -53,11 +53,18 @@
         { key
         , msg
         }).
+-type delayed_message() :: #delayed_message{}.
 
 -define(TAB, ?MODULE).
 -define(SERVER, ?MODULE).
 -define(MAX_INTERVAL, 4294967).
 
+-type state() :: #{ publish_at := non_neg_integer()
+                  , timer := timer:tref() | undefined
+                  , stats_timer => timer:tref() | undefined
+                  , stats_fun => function()
+                  }.
+
 %%--------------------------------------------------------------------
 %% Mnesia bootstrap
 %%--------------------------------------------------------------------
@@ -124,7 +131,7 @@ on_message_publish(Msg) ->
 start_link() ->
     gen_server:start_link({local, ?SERVER}, ?MODULE, [], []).
 
--spec(store(#delayed_message{}) -> ok).
+-spec(store(delayed_message()) -> ok).
 store(DelayedMsg) ->
     gen_server:call(?SERVER, {store, DelayedMsg}, infinity).
 
@@ -134,7 +141,9 @@ store(DelayedMsg) ->
 
 init([]) ->
     {ok, ensure_stats_event(
-           ensure_publish_timer(#{timer => undefined, publish_at => 0}))}.
+           ensure_publish_timer(#{timer => undefined,
+                                  publish_at => 0,
+                                  stats_timer => undefined}))}.
 
 handle_call({store, DelayedMsg = #delayed_message{key = Key}}, _From, State) ->
     ok = mnesia:dirty_write(?TAB, DelayedMsg),
@@ -163,8 +172,9 @@ handle_info(Info, State) ->
     ?LOG(error, "Unexpected info: ~p", [Info]),
     {noreply, State}.
 
-terminate(_Reason, #{timer := TRef}) ->
-    emqx_misc:cancel_timer(TRef).
+terminate(_Reason, #{timer := PublishTimer} = State) ->
+    emqx_misc:cancel_timer(PublishTimer),
+    emqx_misc:cancel_timer(maps:get(stats_timer, State, undefined)).
 
 code_change({down, Vsn}, State, _Extra) when Vsn =:= "4.3.0" ->
     NState = maps:with([timer, publish_at], State),
@@ -179,12 +189,14 @@ code_change(Vsn, State, _Extra) when Vsn =:= "4.3.0" ->
 %%--------------------------------------------------------------------
 
 %% Ensure the stats
+-spec ensure_stats_event(state()) -> state().
 ensure_stats_event(State) ->
     StatsFun = emqx_stats:statsfun('delayed.count', 'delayed.max'),
     {ok, StatsTimer} = timer:send_interval(timer:seconds(1), stats),
     State#{stats_fun => StatsFun, stats_timer => StatsTimer}.
 
 %% Ensure publish timer
+-spec ensure_publish_timer(state()) -> state().
 ensure_publish_timer(State) ->
     ensure_publish_timer(mnesia:dirty_first(?TAB), State).
 
@@ -222,4 +234,3 @@ do_publish(Key = {Ts, _Id}, Now, Acc) when Ts =< Now ->
 
 -spec(delayed_count() -> non_neg_integer()).
 delayed_count() -> mnesia:table_info(?TAB, size).
-
diff --git a/lib-ce/emqx_modules/src/emqx_modules.app.src b/lib-ce/emqx_modules/src/emqx_modules.app.src
index 47a3d8888..ccc3a4c28 100644
--- a/lib-ce/emqx_modules/src/emqx_modules.app.src
+++ b/lib-ce/emqx_modules/src/emqx_modules.app.src
@@ -1,6 +1,6 @@
 {application, emqx_modules,
  [{description, "EMQ X Module Management"},
-  {vsn, "4.3.4"},
+  {vsn, "4.3.5"},
   {modules, []},
   {applications, [kernel,stdlib]},
   {mod, {emqx_modules_app, []}},
diff --git a/lib-ce/emqx_modules/src/emqx_modules.appup.src b/lib-ce/emqx_modules/src/emqx_modules.appup.src
index 1b9eeec84..a82421aec 100644
--- a/lib-ce/emqx_modules/src/emqx_modules.appup.src
+++ b/lib-ce/emqx_modules/src/emqx_modules.appup.src
@@ -1,33 +1,29 @@
-%% -*-: erlang -*-
+%% -*- mode: erlang -*-
+%% Unless you know what you are doing, DO NOT edit manually!!
 {VSN,
-  [
-    {<<"4\\.3\\.[2-3]">>, [
-      {load_module, emqx_mod_presence, brutal_purge, soft_purge, []}
-    ]},
-    {"4.3.1", [
-      {load_module, emqx_mod_presence, brutal_purge, soft_purge, []},
-      {load_module, emqx_mod_api_topic_metrics, brutal_purge, soft_purge, []}
-    ]},
-    {"4.3.0", [
-      {update, emqx_mod_delayed, {advanced, []}},
-      {load_module, emqx_mod_presence, brutal_purge, soft_purge, []},
-      {load_module, emqx_mod_api_topic_metrics, brutal_purge, soft_purge, []}
-    ]},
-    {<<".*">>, []}
-  ],
-  [
-    {<<"4\\.3\\.[2-3]">>, [
-      {load_module, emqx_mod_presence, brutal_purge, soft_purge, []}
-    ]},
-    {"4.3.1", [
-      {load_module, emqx_mod_presence, brutal_purge, soft_purge, []},
-      {load_module, emqx_mod_api_topic_metrics, brutal_purge, soft_purge, []}
-    ]},
-    {"4.3.0", [
-      {update, emqx_mod_delayed, {advanced, []}},
-      {load_module, emqx_mod_presence, brutal_purge, soft_purge, []},
-      {load_module, emqx_mod_api_topic_metrics, brutal_purge, soft_purge, []}
-    ]},
-    {<<".*">>, []}
-  ]
-}.
+  [{"4.3.4",[{load_module,emqx_mod_delayed,brutal_purge,soft_purge,[]}]},
+   {<<"4\\.3\\.[2-3]">>,
+    [{load_module,emqx_mod_delayed,brutal_purge,soft_purge,[]},
+     {load_module,emqx_mod_presence,brutal_purge,soft_purge,[]}]},
+   {"4.3.1",
+    [{load_module,emqx_mod_delayed,brutal_purge,soft_purge,[]},
+     {load_module,emqx_mod_presence,brutal_purge,soft_purge,[]},
+     {load_module,emqx_mod_api_topic_metrics,brutal_purge,soft_purge,[]}]},
+   {"4.3.0",
+    [{update,emqx_mod_delayed,{advanced,[]}},
+     {load_module,emqx_mod_presence,brutal_purge,soft_purge,[]},
+     {load_module,emqx_mod_api_topic_metrics,brutal_purge,soft_purge,[]}]},
+   {<<".*">>,[]}],
+  [{"4.3.4",[{load_module,emqx_mod_delayed,brutal_purge,soft_purge,[]}]},
+   {<<"4\\.3\\.[2-3]">>,
+    [{load_module,emqx_mod_delayed,brutal_purge,soft_purge,[]},
+     {load_module,emqx_mod_presence,brutal_purge,soft_purge,[]}]},
+   {"4.3.1",
+    [{load_module,emqx_mod_delayed,brutal_purge,soft_purge,[]},
+     {load_module,emqx_mod_presence,brutal_purge,soft_purge,[]},
+     {load_module,emqx_mod_api_topic_metrics,brutal_purge,soft_purge,[]}]},
+   {"4.3.0",
+    [{update,emqx_mod_delayed,{advanced,[]}},
+     {load_module,emqx_mod_presence,brutal_purge,soft_purge,[]},
+     {load_module,emqx_mod_api_topic_metrics,brutal_purge,soft_purge,[]}]},
+   {<<".*">>,[]}]}.