diff --git a/apps/emqtt/include/emqtt.hrl b/apps/emqtt/include/emqtt.hrl
index 1184aab01..bbd1f95c4 100644
--- a/apps/emqtt/include/emqtt.hrl
+++ b/apps/emqtt/include/emqtt.hrl
@@ -61,6 +61,8 @@
     qos    = ?QOS_0 :: mqtt_qos(),
     retain = false  :: boolean(),
     dup    = false  :: boolean(),
+    %% $SYS message flag
+    sys    = false  :: boolean(),
     msgid           :: mqtt_msgid(),
     payload         :: binary()
 }).
diff --git a/apps/emqttd/src/emqttd_cluster.erl b/apps/emqttd/src/emqttd_cluster.erl
deleted file mode 100644
index bd5a1a2ac..000000000
--- a/apps/emqttd/src/emqttd_cluster.erl
+++ /dev/null
@@ -1,40 +0,0 @@
-%%%-----------------------------------------------------------------------------
-%%% Copyright (c) 2012-2015 eMQTT.IO, All Rights Reserved.
-%%%
-%%% Permission is hereby granted, free of charge, to any person obtaining a copy
-%%% of this software and associated documentation files (the "Software"), to deal
-%%% in the Software without restriction, including without limitation the rights
-%%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-%%% copies of the Software, and to permit persons to whom the Software is
-%%% furnished to do so, subject to the following conditions:
-%%%
-%%% The above copyright notice and this permission notice shall be included in all
-%%% copies or substantial portions of the Software.
-%%%
-%%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-%%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-%%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-%%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-%%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-%%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-%%% SOFTWARE.
-%%%-----------------------------------------------------------------------------
-%%% @doc
-%%% emqttd cluster to monitor clusted nodes.
-%%%
-%%% @end
-%%%-----------------------------------------------------------------------------
--module(emqttd_cluster).
-
--author("Feng Lee <feng@emqtt.io>").
-
--export([running_nodes/0]).
-
-%%------------------------------------------------------------------------------
-%% @doc Get running nodes
-%% @end
-%%------------------------------------------------------------------------------
-%%TODO: remove...
-running_nodes() ->
-    mnesia:system_info(running_db_nodes).
-
diff --git a/apps/emqttd/src/emqttd_mod_presence.erl b/apps/emqttd/src/emqttd_mod_presence.erl
index 981cb4350..3e5dbccb2 100644
--- a/apps/emqttd/src/emqttd_mod_presence.erl
+++ b/apps/emqttd/src/emqttd_mod_presence.erl
@@ -26,6 +26,8 @@
 %%%-----------------------------------------------------------------------------
 -module(emqttd_mod_presence).
 
+-author("Feng Lee <feng@emqtt.io>").
+
 -include_lib("emqtt/include/emqtt.hrl").
 
 -include("emqttd.hrl").
diff --git a/rel/files/emqttd.config b/rel/files/emqttd.config
index 39e92334e..977101cce 100644
--- a/rel/files/emqttd.config
+++ b/rel/files/emqttd.config
@@ -1,4 +1,4 @@
-%% -*- mode: erlang;erlang-indent-level: 4;indent-tabs-mode: nil -*-
+h% -*- mode: erlang;erlang-indent-level: 4;indent-tabs-mode: nil -*-
 %% ex: ft=erlang ts=4 sw=4 et
 [{kernel, 
 	[{start_timer, true},
@@ -87,13 +87,25 @@
         ]},
         %% Session
         {session, [
-            %% Expired after 24 hours
-            {expires, 24},
-            %% Max offline message queue
-            {max_queue, 100},
-            %% Store Qos0?
-            {store_qos0, false}
-        ]}
+            %% Expired after 2 days
+            {expired_after, 48},
+            %% Max number of QoS 1 and 2 messages that can be “in flight” at one time.
+            {max_inflight_messages, 20},
+            %% Max retries for unacknolege Qos1/2 messages
+            {max_unack_retries, 3},
+            %% Retry after 10 seconds
+            {unack_retry_after, 10}
+        ]},
+        {queue, [
+            %% Max messages queued when client is disconnected, or inflight messsages is overload
+            {max_queued_messages, 100},
+            %% High watermark of queued messsages
+            {high_queue_watermark, 0.6},
+            %% Low watermark of queued messsages
+            {low_queue_watermark, 0.2},
+            %% Queue Qos0 offline messages?
+            {queue_qos0_messages, false}
+        ]},
     ]},
     %% Broker Options
     {broker, [