diff --git a/apps/emqx_stomp/src/emqx_stomp_connection.erl b/apps/emqx_stomp/src/emqx_stomp_connection.erl
index 6cf1371e6..5a8b7a92c 100644
--- a/apps/emqx_stomp/src/emqx_stomp_connection.erl
+++ b/apps/emqx_stomp/src/emqx_stomp_connection.erl
@@ -26,8 +26,7 @@
 -logger_header("[Stomp-Conn]").
 
 -import(emqx_misc,
-        [ maybe_apply/2
-        , start_timer/2
+        [ start_timer/2
         ]).
 
 -export([ start_link/3
@@ -92,6 +91,13 @@
 
 -define(ENABLED(X), (X =/= undefined)).
 
+-dialyzer({nowarn_function, [ ensure_stats_timer/2
+                            ]}).
+
+-dialyzer({no_return, [ init/1
+                      , init_state/3
+                      ]}).
+
 start_link(Transport, Sock, ProtoEnv) ->
     {ok, proc_lib:spawn_link(?MODULE, init, [[Transport, Sock, ProtoEnv]])}.
 
@@ -115,13 +121,7 @@ info(sockname, #state{sockname = Sockname}) ->
 info(sockstate, #state{sockstate = SockSt}) ->
     SockSt;
 info(active_n, #state{active_n = ActiveN}) ->
-    ActiveN;
-info(stats_timer, #state{stats_timer = StatsTimer}) ->
-    StatsTimer;
-info(limit_timer, #state{limit_timer = LimitTimer}) ->
-    LimitTimer;
-info(limiter, #state{limiter = Limiter}) ->
-    maybe_apply(fun emqx_limiter:info/1, Limiter).
+    ActiveN.
 
 -spec stats(pid()|state()) -> emqx_types:stats().
 stats(CPid) when is_pid(CPid) ->
@@ -216,6 +216,12 @@ send(Data, Transport, Sock, ConnPid) ->
 heartbeat(Transport, Sock) ->
     Transport:send(Sock, <<$\n>>).
 
+handle_call(info, _From, State) ->
+    {reply, info(State), State};
+
+handle_call(stats, _From, State) ->
+    {reply, stats(State), State};
+
 handle_call(discard, _From, State) ->
     %% TODO: send the DISCONNECT packet?
     shutdown_and_reply(discared, ok, State);
diff --git a/apps/emqx_stomp/src/emqx_stomp_protocol.erl b/apps/emqx_stomp/src/emqx_stomp_protocol.erl
index c2851895b..eb628ce47 100644
--- a/apps/emqx_stomp/src/emqx_stomp_protocol.erl
+++ b/apps/emqx_stomp/src/emqx_stomp_protocol.erl
@@ -20,6 +20,7 @@
 -include("emqx_stomp.hrl").
 
 -include_lib("emqx/include/emqx.hrl").
+-include_lib("emqx/include/types.hrl").
 -include_lib("emqx/include/logger.hrl").
 -include_lib("emqx/include/emqx_mqtt.hrl").
 
@@ -55,7 +56,7 @@
           %% Stomp ClientInfo
           clientinfo :: emqx_types:clientinfo(),
           %% Stomp Heartbeats
-          heart_beats :: emqx_stomp_hearbeat:heartbeat(),
+          heart_beats :: maybe(emqx_stomp_hearbeat:heartbeat()),
           %% Stomp Connection State
           connected = false,
           %% Timers
@@ -65,13 +66,13 @@
           %% Subscriptions
           subscriptions = #{},
           %% Send function
-          sendfun :: function(),
+          sendfun :: {function(), list()},
           %% Heartbeat function
-          heartfun :: function(),
+          heartfun :: {function(), list()},
           %% The confs for the connection
           %% TODO: put these configs into a public mem?
-          allow_anonymous,
-          default_user
+          allow_anonymous :: maybe(boolean()),
+          default_user :: maybe(list())
          }).
 
 -define(TIMER_TABLE, #{
@@ -96,6 +97,10 @@
                      awaiting_rel_max
                     ]).
 
+-dialyzer({nowarn_function, [ check_acl/3
+                            , init/2
+                            ]}).
+
 -type(pstate() :: #pstate{}).
 
 %% @doc Init protocol
@@ -417,7 +422,7 @@ send(Msg = #message{topic = Topic, headers = Headers, payload = Payload},
             {error, dropped, State}
     end;
 
-send(Frame, State = #pstate{sendfun = {Fun, Args}}) ->
+send(Frame, State = #pstate{sendfun = {Fun, Args}}) when is_record(Frame, stomp_frame) ->
     ?LOG(info, "SEND Frame: ~s", [emqx_stomp_frame:format(Frame)]),
     Data = emqx_stomp_frame:serialize(Frame),
     ?LOG(debug, "SEND ~p", [Data]),
@@ -681,7 +686,7 @@ allow_anonymous(#pstate{allow_anonymous = AllowAnonymous}) ->
     AllowAnonymous.
 
 ensure_connected(State = #pstate{conninfo = ConnInfo,
-                                  clientinfo = ClientInfo}) ->
+                                 clientinfo = ClientInfo}) ->
     NConnInfo = ConnInfo#{
                   connected => true,
                   connected_at => erlang:system_time(millisecond)
diff --git a/src/emqx_types.erl b/src/emqx_types.erl
index fbe62e4b2..0c15bd288 100644
--- a/src/emqx_types.erl
+++ b/src/emqx_types.erl
@@ -94,7 +94,8 @@
 -type(ver() :: ?MQTT_PROTO_V3
              | ?MQTT_PROTO_V4
              | ?MQTT_PROTO_V5
-             | non_neg_integer()).
+             | non_neg_integer()
+             | binary()).
 
 -type(qos() :: ?QOS_0 | ?QOS_1 | ?QOS_2).
 -type(qos_name() :: qos0 | at_most_once |