diff --git a/apps/emqx_stomp/src/emqx_stomp_protocol.erl b/apps/emqx_stomp/src/emqx_stomp_protocol.erl
index eb628ce47..0dbfbb13b 100644
--- a/apps/emqx_stomp/src/emqx_stomp_protocol.erl
+++ b/apps/emqx_stomp/src/emqx_stomp_protocol.erl
@@ -75,6 +75,8 @@
           default_user :: maybe(list())
          }).
 
+-define(DEFAULT_SUB_ACK, <<"auto">>).
+
 -define(TIMER_TABLE, #{
           incoming_timer => incoming,
           outgoing_timer => outgoing,
@@ -287,12 +289,17 @@ received(#stomp_frame{command = <<"SUBSCRIBE">>, headers = Headers},
             State = #pstate{subscriptions = Subs}) ->
     Id    = header(<<"id">>, Headers),
     Topic = header(<<"destination">>, Headers),
-    Ack   = header(<<"ack">>, Headers, <<"auto">>),
+    Ack   = header(<<"ack">>, Headers, ?DEFAULT_SUB_ACK),
 
     case find_sub_by_id(Id, Subs) of
-        {Topic, #{sub_props := #{id := Id, ack := Ack}}} ->
+        {Topic, #{sub_props := #{id := Id}}} ->
             ?LOG(info, "Subscription has established: ~s", [Topic]),
             maybe_send_receipt(receipt_id(Headers), State);
+        {InuseTopic, #{sub_props := #{id := InuseId}}} ->
+            ?LOG(info, "Subscription id ~p inused by topic: ~s, "
+                       "request topic: ~s", [InuseId, InuseTopic, Topic]),
+            send(error_frame(receipt_id(Headers),
+                             ["Request sub-id ", Id, " inused "]), State);
         undefined ->
             case check_acl(subscribe, Topic, State) of
                 allow ->
@@ -466,8 +473,9 @@ timeout(_TRef, clean_trans, State = #pstate{transaction = Trans}) ->
 
 handle_info({subscribe, TopicFilters}, State) ->
     NState = lists:foldl(
-        fun({TopicFilter, SubOpts}, StateAcc) ->
-            do_subscribe(TopicFilter, SubOpts#{is_new => true}, StateAcc)
+        fun({TopicFilter, SubOpts}, StateAcc = #pstate{subscriptions = Subs}) ->
+            NSubOpts = enrich_sub_opts(SubOpts, Subs),
+            do_subscribe(TopicFilter, NSubOpts, StateAcc)
         end, State, parse_topic_filters(TopicFilters)),
     {ok, NState};
 
@@ -646,7 +654,7 @@ do_subscribe(TopicFilter, SubOpts,
     NSubOpts = SubOpts#{is_new => true},
     _ = run_hooks('session.subscribed',
                   [ClientInfo, TopicFilter, NSubOpts]),
-
+    send_event_to_self(updated),
     State#pstate{subscriptions = maps:put(TopicFilter, SubOpts, Subs)}.
 
 do_unsubscribe(TopicFilter, SubOpts,
@@ -654,7 +662,7 @@ do_unsubscribe(TopicFilter, SubOpts,
     ok = emqx_broker:unsubscribe(TopicFilter),
     _ = run_hooks('session.unsubscribe',
                   [ClientInfo, TopicFilter, SubOpts]),
-
+    send_event_to_self(updated),
     State#pstate{subscriptions = maps:remove(TopicFilter, Subs)}.
 
 find_sub_by_topic(Topic, Subs) ->
@@ -677,6 +685,21 @@ is_acl_enabled(_) ->
     %% TODO: configs from somewhere
     true.
 
+%% automaticly fill the next sub-id and ack if sub-id is absent
+enrich_sub_opts(SubOpts0, Subs) ->
+    SubOpts = maps:merge(?DEFAULT_SUBOPTS, SubOpts0),
+    SubProps = maps:get(sub_props, SubOpts, #{}),
+    SubOpts#{sub_props =>
+             maps:merge(#{id => next_sub_id(Subs),
+                          ack => ?DEFAULT_SUB_ACK}, SubProps)}.
+
+next_sub_id(Subs) ->
+    Ids = maps:fold(fun(_, SubOpts, Acc) ->
+        [binary_to_integer(
+           maps:get(id, maps:get(sub_props, SubOpts, #{}), <<"0">>)) | Acc]
+    end, [], Subs),
+    integer_to_binary(lists:max(Ids) + 1).
+
 %%--------------------------------------------------------------------
 %% helpers
 
@@ -691,8 +714,7 @@ ensure_connected(State = #pstate{conninfo = ConnInfo,
                   connected => true,
                   connected_at => erlang:system_time(millisecond)
                  },
-    %% send connected event
-    self() ! {event, connected},
+    send_event_to_self(connected),
     ok = run_hooks('client.connected', [ClientInfo, NConnInfo]),
     State#pstate{conninfo  = NConnInfo,
                  connected = true
@@ -703,6 +725,9 @@ ensure_disconnected(Reason, State = #pstate{conninfo = ConnInfo, clientinfo = Cl
     ok = run_hooks('client.disconnected', [ClientInfo, Reason, NConnInfo]),
     State#pstate{conninfo = NConnInfo, connected = false}.
 
+send_event_to_self(Name) ->
+    self() ! {event, Name}, ok.
+
 run_hooks(Name, Args) ->
     emqx_hooks:run(Name, Args).