diff --git a/src/emqttd_mod_rewrite.erl b/src/emqttd_mod_rewrite.erl
index edd6ac41a..653fb49c7 100644
--- a/src/emqttd_mod_rewrite.erl
+++ b/src/emqttd_mod_rewrite.erl
@@ -44,9 +44,9 @@ rewrite_subscribe({_ClientId, _Username}, {Topic, Opts}, Sections) ->
     lager:info("Rewrite subscribe: ~p", [{Topic, Opts}]),
     {ok, {match_topic(Topic, Sections), Opts}}.
 
-rewrite_unsubscribe({_ClientId, _Username}, {Topic, Opts}, Sections) ->
-    lager:info("Rewrite unsubscribe: ~p", [{Topic, Opts}]),
-    {ok, {match_topic(Topic, Sections), Opts}}.
+rewrite_unsubscribe({_ClientId, _Username}, Topic, Sections) ->
+    lager:info("Rewrite unsubscribe: ~p", [Topic]),
+    {ok, match_topic(Topic, Sections)}.
 
 rewrite_publish(Message=#mqtt_message{topic = Topic}, Sections) ->
     %%TODO: this will not work if the client is always online.
diff --git a/src/emqttd_pubsub.erl b/src/emqttd_pubsub.erl
index 1af6274bf..487181a0e 100644
--- a/src/emqttd_pubsub.erl
+++ b/src/emqttd_pubsub.erl
@@ -26,7 +26,7 @@
 -export([start_link/3, subscribe/2, unsubscribe/2, publish/2,
          async_subscribe/2, async_unsubscribe/2]).
 
--export([subscribers/1]).
+-export([subscribers/1, dispatch/2]).
 
 %% gen_server.
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
diff --git a/src/emqttd_session.erl b/src/emqttd_session.erl
index 6c4ab5c97..85701e249 100644
--- a/src/emqttd_session.erl
+++ b/src/emqttd_session.erl
@@ -84,7 +84,7 @@
         packet_id = 1,
         
         %% Client’s subscriptions.
-        subscriptions :: dict:dict(),
+        subscriptions :: map(),
 
         %% Inflight qos1, qos2 messages sent to the client but unacked,
         %% QoS 1 and QoS 2 messages which have been sent to the Client,
@@ -323,7 +323,7 @@ handle_cast({unsubscribe, TopicTable}, Session = #session{client_id     = Client
                     {ok, _Qos} ->
                         emqttd:unsubscribe(Topic, ClientId),
                         emqttd:run_hooks('session.unsubscribed', [ClientId, Username], {Topic, Opts}),
-                        dict:erase(Topic, SubMap);
+                        maps:remove(Topic, SubMap);
                     error ->
                         SubMap
                 end
@@ -561,8 +561,8 @@ dispatch(Msg = #mqtt_message{qos = QoS}, Session = #session{message_queue = MsgQ
             hibernate(Session#session{message_queue = emqttd_mqueue:in(Msg, MsgQ)})
     end.
 
-tune_qos(Topic, Msg = #mqtt_message{qos = PubQos}, Subscriptions) ->
-    case dict:find(Topic, Subscriptions) of
+tune_qos(Topic, Msg = #mqtt_message{qos = PubQos}, SubMap) ->
+    case maps:find(Topic, SubMap) of
         {ok, SubQos} when PubQos > SubQos ->
             Msg#mqtt_message{qos = SubQos};
         {ok, _SubQos} ->