diff --git a/src/emqx_channel.erl b/src/emqx_channel.erl
index 19d361515..117cb3fe2 100644
--- a/src/emqx_channel.erl
+++ b/src/emqx_channel.erl
@@ -334,30 +334,26 @@ handle_in(Packet = ?UNSUBSCRIBE_PACKET(PacketId, Properties, TopicFilters),
 handle_in(?PACKET(?PINGREQ), Channel) ->
     {ok, ?PACKET(?PINGRESP), Channel};
 
-handle_in(?DISCONNECT_PACKET(RC, Props),
-          Channel = #channel{conninfo = ConnInfo = #{expiry_interval := OldInterval}}) ->
+handle_in(?DISCONNECT_PACKET(ReasonCode, Properties), Channel = #channel{session = Session,
+                                                                         conninfo = ConnInfo = #{expiry_interval := OldInterval}}) ->
+    OldInterval = emqx_session:info(expiry_interval, Session),
     Interval = emqx_mqtt_props:get('Session-Expiry-Interval', Props, OldInterval),
     case OldInterval =:= 0 andalso Interval =/= OldInterval of
         true ->
             handle_out({disconnect, ?RC_PROTOCOL_ERROR}, Channel);
         false ->
-            Channel1 = case RC of
-                           ?RC_SUCCESS -> Channel#channel{will_msg = undefined};
-                           _ -> Channel
-                       end,
-            Channel2 = Channel1#channel{conninfo = ConnInfo#{expiry_interval => Interval}},
-            case Interval of
-                ?UINT_MAX ->
-                    {ok, ensure_timer(will_timer, Channel2)};
-                Int when Int > 0 ->
-                    {ok, ensure_timer([will_timer, expire_timer], Channel2)};
-                _Other ->
-                    Reason = case RC of
-                                 ?RC_SUCCESS -> normal;
-                                 _ -> emqx_reason_codes:name(RC, maps:get(proto_ver, ConnInfo))
-                             end,
-                    {stop, {shutdown, Reason}, Channel2}
-            end
+            Reason = case ReasonCode of
+                         ?RC_SUCCESS -> normal;
+                         _ ->
+                             ProtoVer = emqx_protocol:info(proto_ver, Protocol),
+                             emqx_reason_codes:name(ReasonCode, ProtoVer)
+                     end,
+            {wait_session_expire, {shutdown, Reason},
+             Channel#channel{session = emqx_session:update_expiry_interval(Interval, Session),
+                             protocol = case ReasonCode of
+                                            ?RC_SUCCESS -> emqx_protocol:clear_will_msg(Protocol);
+                                            _ -> Protocol
+                                        end}}
     end;
 
 handle_in(?AUTH_PACKET(), Channel) ->
@@ -366,7 +362,7 @@ handle_in(?AUTH_PACKET(), Channel) ->
 
 handle_in(Packet, Channel) ->
     ?LOG(error, "Unexpected incoming: ~p", [Packet]),
-    {stop, {shutdown, unexpected_incoming_packet}, Channel}.
+    handle_out({disconnect, ?RC_MALFORMED_PACKET}, Channel).
 
 %%--------------------------------------------------------------------
 %% Process Connect
@@ -562,9 +558,6 @@ handle_out({deliver, Delivers}, Channel = #channel{session = Session}) ->
             {ok, Channel#channel{session = NSession}}
     end;
 
-handle_out({publish, [Publish]}, Channel) ->
-    handle_out(Publish, Channel);
-
 handle_out({publish, Publishes}, Channel) when is_list(Publishes) ->
     Packets = lists:foldl(
                 fun(Publish, Acc) ->
@@ -621,10 +614,10 @@ handle_out({disconnect, ReasonCode}, Channel = #channel{conninfo = ConnInfo}) ->
         ?MQTT_PROTO_V5 ->
             Reason = emqx_reason_codes:name(ReasonCode),
             Packet = ?DISCONNECT_PACKET(ReasonCode),
-            {stop, {shutdown, Reason}, Packet, Channel};
+            {wait_session_expire, {shutdown, Reason}, Packet, Channel};
         ProtoVer ->
             Reason = emqx_reason_codes:name(ReasonCode, ProtoVer),
-            {stop, {shutdown, Reason}, Channel}
+            {wait_session_expire, {shutdown, Reason}, Channel}
     end;
 
 handle_out({Type, Data}, Channel) ->
@@ -696,17 +689,29 @@ handle_info({unsubscribe, TopicFilters}, Channel = #channel{client = ClientInfo}
 handle_info(disconnected, Channel = #channel{connected = undefined}) ->
     shutdown(closed, Channel);
 
-handle_info(disconnected, Channel = #channel{conninfo = #{expiry_interval := Interval},
+handle_info(disconnected, Channel = #channel{connected = false}) ->
+    {ok, Channel};
+
+handle_info(disconnected, Channel = #channel{conninfo = #{expiry_interval := ExpiryInterval},
+                                             client   = ClientInfo = #{zone := Zone},
+                                             session  = Session,
                                              will_msg = WillMsg}) ->
-    %% TODO: Why handle will_msg here?
-    publish_will_msg(WillMsg),
-    NChannel = Channel#channel{will_msg = undefined},
-    case Interval of
+    emqx_zone:enable_flapping_detect(Zone) andalso emqx_flapping:detect(ClientInfo),
+    Channel1 = ensure_disconnected(Channel),
+    Channel2 = case timer:seconds(will_delay_interval(WillMsg)) of
+                   0 ->
+                       publish_will_msg(WillMsg),
+                       Channel1#channel{will_msg = undefined};
+                   _ ->
+                       ensure_timer(will_timer, Channel1)
+               end,
+    case ExpiryInterval of
         ?UINT_MAX ->
-            {ok, ensure_disconnected(NChannel)};
+            {ok, Channel2};
         Int when Int > 0 ->
-            {ok, ensure_timer(expire_timer, ensure_disconnected(NChannel))};
-        _Other -> shutdown(closed, NChannel)
+            {ok, ensure_timer(expire_timer, Channel2)};
+        _Other ->
+            shutdown(closed, Channel2)
     end;
 
 handle_info(Info, Channel) ->
@@ -735,7 +740,7 @@ handle_timeout(TRef, {keepalive, StatVal},
             NChannel = Channel#channel{keepalive = NKeepalive},
             {ok, reset_timer(alive_timer, NChannel)};
         {error, timeout} ->
-            {stop, {shutdown, keepalive_timeout}, Channel}
+            {wait_session_expire, {shutdown, keepalive_timeout}, Channel}
     end;
 
 handle_timeout(TRef, retry_delivery,
@@ -818,7 +823,11 @@ interval(expire_timer, #channel{conninfo = ConnInfo}) ->
     timer:seconds(maps:get(expiry_interval, ConnInfo));
 interval(will_timer, #channel{will_msg = WillMsg}) ->
     %% TODO: Ensure the header exists.
-    timer:seconds(emqx_message:get_header('Will-Delay-Interval', WillMsg)).
+    timer:seconds(will_delay_interval(WillMsg)).
+
+will_delay_interval(undefined) -> 0;
+will_delay_interval(WillMsg) ->
+    emqx_message:get_header('Will-Delay-Interval', WillMsg, 0).
 
 %%--------------------------------------------------------------------
 %% Terminate
@@ -826,9 +835,16 @@ interval(will_timer, #channel{will_msg = WillMsg}) ->
 
 terminate(normal, #channel{conninfo = ConnInfo, client = ClientInfo}) ->
     ok = emqx_hooks:run('client.disconnected', [ClientInfo, normal, ConnInfo]);
+terminate({shutdown, Reason}, #channel{conninfo = ConnInfo, client = ClientInfo,})
+    when Reason =:= kicked orelse Reason =:= discarded orelse Reason =:= takeovered ->
+    ok = emqx_hooks:run('client.disconnected', [ClientInfo, Reason, ConnInfo]);
 terminate(Reason, #channel{conninfo = ConnInfo, client = ClientInfo, will_msg = WillMsg}) ->
     publish_will_msg(WillMsg),
     ok = emqx_hooks:run('client.disconnected', [ClientInfo, Reason, ConnInfo]).
+    if
+        Protocol == undefined -> ok;
+        true -> publish_will_msg(emqx_protocol:info(will_msg, Protocol))
+    end.
 
 -spec(received(pos_integer(), channel()) -> channel()).
 received(Oct, Channel) ->
diff --git a/src/emqx_connection.erl b/src/emqx_connection.erl
index 74ff9df82..f4aeede00 100644
--- a/src/emqx_connection.erl
+++ b/src/emqx_connection.erl
@@ -224,10 +224,13 @@ idle(cast, {incoming, Packet = ?CONNECT_PACKET(ConnPkt)}, State) ->
     SuccFun = fun(NewSt) -> {next_state, connected, NewSt} end,
     handle_incoming(Packet, SuccFun, NState);
 
-idle(cast, {incoming, Packet}, State) ->
+idle(cast, {incoming, Packet}, State) when is_record(Packet, mqtt_packet) ->
     ?LOG(warning, "Unexpected incoming: ~p", [Packet]),
     shutdown(unexpected_incoming_packet, State);
 
+idle(cast, {incoming, {error, Reason}}, State) ->
+    shutdown(Reason, State);
+
 idle(EventType, Content, State) ->
     ?HANDLE(EventType, Content, State).
 
@@ -241,6 +244,17 @@ connected(enter, _PrevSt, State) ->
 connected(cast, {incoming, Packet}, State) when is_record(Packet, mqtt_packet) ->
     handle_incoming(Packet, fun keep_state/1, State);
 
+connected(cast, {incoming, {error, Reason}}, State = #connection{chan_state = ChanState}) ->
+    case emqx_channel:handle_out({disconnect, emqx_reason_codes:mqtt_frame_error(Reason)}, ChanState) of
+        {wait_session_expire, _, NChanState} ->
+            ?LOG(debug, "Disconnect and wait for session to expire due to ~p", [Reason]),
+            {next_state, disconnected, State#connection{chan_state= NChanState}};
+        {wait_session_expire, _, OutPackets, NChanState} ->
+            ?LOG(debug, "Disconnect and wait for session to expire due to ~p", [Reason]),
+            NState = State#connection{chan_state= NChanState},
+            {next_state, disconnected, handle_outgoing(OutPackets, fun(NewSt) -> NewSt end, NState)}
+    end;
+
 connected(info, Deliver = {deliver, _Topic, _Msg}, State) ->
     handle_deliver(emqx_misc:drain_deliver([Deliver]), State);
 
@@ -408,8 +422,7 @@ process_incoming(Data, State) ->
 process_incoming(<<>>, Packets, State) ->
     {keep_state, State, next_incoming_events(Packets)};
 
-process_incoming(Data, Packets, State = #connection{parse_state = ParseState,
-                                                    chan_state  = ChanState}) ->
+process_incoming(Data, Packets, State = #connection{parse_state = ParseState}) ->
     try emqx_frame:parse(Data, ParseState) of
         {more, NParseState} ->
             NState = State#connection{parse_state = NParseState},
@@ -418,32 +431,16 @@ process_incoming(Data, Packets, State = #connection{parse_state = ParseState,
             NState = State#connection{parse_state = NParseState},
             process_incoming(Rest, [Packet|Packets], NState);
         {error, Reason} ->
-            shutdown(Reason, State)
+            {keep_state, State, next_incoming_events({error, Reason})}
     catch
         error:Reason:Stk ->
-            ?LOG(error, "Parse failed for ~p~nStacktrace:~p~nError data:~p", [Reason, Stk, Data]),
-            Result =
-                case emqx_channel:info(connected, ChanState) of
-                    undefined ->
-                        emqx_channel:handle_out({connack, emqx_reason_codes:mqtt_frame_error(Reason)}, ChanState);
-                    true ->
-                        emqx_channel:handle_out({disconnect, emqx_reason_codes:mqtt_frame_error(Reason)}, ChanState);
-                    _ ->
-                        ignore
-                end,
-            case Result of
-                {stop, Reason0, OutPackets, NChanState} ->
-                    Shutdown = fun(NewSt) -> stop(Reason0, NewSt) end,
-                    NState = State#connection{chan_state = NChanState},
-                    handle_outgoing(OutPackets, Shutdown, NState);
-                {stop, Reason0, NChanState} ->
-                    stop(Reason0, State#connection{chan_state = NChanState});
-                ignore ->
-                    keep_state(State)
-            end
+            ?LOG(error, "~nParse failed for ~p~nStacktrace: ~p~nError data:~p", [Reason, Stk, Data]),
+            {keep_state, State, next_incoming_events({error, Reason})}
     end.
 
 -compile({inline, [next_incoming_events/1]}).
+next_incoming_events({error, Reason}) ->
+    [next_event(cast, {incoming, {error, Reason}})];
 next_incoming_events(Packets) ->
     [next_event(cast, {incoming, Packet}) || Packet <- Packets].
 
@@ -459,14 +456,19 @@ handle_incoming(Packet = ?PACKET(Type), SuccFun,
         {ok, NChanState} ->
             SuccFun(State#connection{chan_state= NChanState});
         {ok, OutPackets, NChanState} ->
-            handle_outgoing(OutPackets, SuccFun,
-                            State#connection{chan_state = NChanState});
+            handle_outgoing(OutPackets, SuccFun, State#connection{chan_state = NChanState});
+        {wait_session_expire, Reason, NChanState} ->
+            ?LOG(debug, "Disconnect and wait for session to expire due to ~p", [Reason]),
+            {next_state, disconnected, State#connection{chan_state = NChanState}};
+        {wait_session_expire, Reason, OutPackets, NChanState} ->
+            ?LOG(debug, "Disconnect and wait for session to expire due to ~p", [Reason]),
+            NState = State#connection{chan_state= NChanState},
+            {next_state, disconnected, handle_outgoing(OutPackets, fun(NewSt) -> NewSt end, NState)};
         {stop, Reason, NChanState} ->
             stop(Reason, State#connection{chan_state = NChanState});
         {stop, Reason, OutPackets, NChanState} ->
-            Shutdown = fun(NewSt) -> stop(Reason, NewSt) end,
-            NState = State#connection{chan_state = NChanState},
-            handle_outgoing(OutPackets, Shutdown, NState)
+            NState = State#connection{chan_state= NChanState},
+            stop(Reason, handle_outgoing(OutPackets, fun(NewSt) -> NewSt end, NState))
     end.
 
 %%-------------------------------------------------------------------
@@ -477,10 +479,7 @@ handle_deliver(Delivers, State = #connection{chan_state = ChanState}) ->
         {ok, NChanState} ->
             keep_state(State#connection{chan_state = NChanState});
         {ok, Packets, NChanState} ->
-            NState = State#connection{chan_state = NChanState},
-            handle_outgoing(Packets, fun keep_state/1, NState);
-        {stop, Reason, NChanState} ->
-            stop(Reason, State#connection{chan_state = NChanState})
+            handle_outgoing(Packets, fun keep_state/1, State#connection{chan_state = NChanState})
     end.
 
 %%--------------------------------------------------------------------
@@ -534,8 +533,10 @@ handle_timeout(TRef, Msg, State = #connection{chan_state = ChanState}) ->
         {ok, NChanState} ->
             keep_state(State#connection{chan_state = NChanState});
         {ok, Packets, NChanState} ->
-            handle_outgoing(Packets, fun keep_state/1,
-                            State#connection{chan_state = NChanState});
+            handle_outgoing(Packets, fun keep_state/1, State#connection{chan_state = NChanState});
+        {wait_session_expire, Reason, NChanState} ->
+            ?LOG(debug, "Disconnect and wait for session to expire due to ~p", [Reason]),
+            {next_state, disconnected, State#connection{chan_state = NChanState}};
         {stop, Reason, NChanState} ->
             stop(Reason, State#connection{chan_state = NChanState})
     end.
diff --git a/src/emqx_flapping.erl b/src/emqx_flapping.erl
index b9187a2e4..ca0e411a0 100644
--- a/src/emqx_flapping.erl
+++ b/src/emqx_flapping.erl
@@ -141,11 +141,11 @@ handle_cast({detected, Flapping = #flapping{client_id  = ClientId,
             %% Log first
             ?LOG(error, "Flapping detected: ~s(~s) disconnected ~w times in ~wms",
                  [ClientId, esockd_net:ntoa(PeerHost), DetectCnt, Duration]),
-            %% TODO: Send Alarm
             %% Banned.
             BannedFlapping = Flapping#flapping{client_id = {banned, ClientId},
                                                banned_at = emqx_time:now_ms()
                                               },
+            alarm_handler:set_alarm({{flapping_detected, ClientId}, BannedFlapping}),
             ets:insert(?FLAPPING_TAB, BannedFlapping);
         false ->
             ?LOG(warning, "~s(~s) disconnected ~w times in ~wms",
@@ -189,9 +189,17 @@ with_flapping_tab(Fun, Args) ->
     end.
 
 expire_flapping(NowTime, #{duration := Duration, banned_interval := Interval}) ->
-    ets:select_delete(?FLAPPING_TAB,
-                      [{#flapping{started_at = '$1', banned_at = undefined, _ = '_'},
-                        [{'<', '$1', NowTime-Duration}], [true]},
-                       {#flapping{client_id = {banned, '_'}, banned_at = '$1', _ = '_'},
-                        [{'<', '$1', NowTime-Interval}], [true]}]).
+    case ets:select(?FLAPPING_TAB,
+                    [{#flapping{started_at = '$1', banned_at = undefined, _ = '_'},
+                      [{'<', '$1', NowTime-Duration}], ['$_']},
+                     {#flapping{client_id = {banned, '_'}, banned_at = '$1', _ = '_'},
+                      [{'<', '$1', NowTime-Interval}], ['$_']}]) of
+        [] -> ok;
+        Flappings ->
+            lists:foreach(fun(Flapping = #flapping{client_id = {banned, ClientId}}) ->
+                              ets:delete_object(?FLAPPING_TAB, Flapping),
+                              alarm_handler:clear_alarm({flapping_detected, ClientId});
+                             (_) -> ok
+                            end, Flappings)
+    end.
 
diff --git a/src/emqx_packet.erl b/src/emqx_packet.erl
index 569008a0c..6b7663b75 100644
--- a/src/emqx_packet.erl
+++ b/src/emqx_packet.erl
@@ -110,6 +110,10 @@ check(#mqtt_packet{variable = SubPkt}) when is_record(SubPkt, mqtt_packet_subscr
 check(#mqtt_packet{variable = UnsubPkt}) when is_record(UnsubPkt, mqtt_packet_unsubscribe) ->
     check(UnsubPkt);
 
+check(#mqtt_packet_publish{topic_name = <<>>, properties = #{'Topic-Alias':= _TopicAlias}}) ->
+    ok;
+check(#mqtt_packet_publish{topic_name = <<>>, properties = #{}}) ->
+    {error, ?RC_PROTOCOL_ERROR};
 check(#mqtt_packet_publish{topic_name = TopicName, properties = Props}) ->
     try emqx_topic:validate(name, TopicName) of
         true -> check_pub_props(Props)
diff --git a/src/emqx_session.erl b/src/emqx_session.erl
index 67b6608b8..434f5f5ed 100644
--- a/src/emqx_session.erl
+++ b/src/emqx_session.erl
@@ -426,7 +426,13 @@ dequeue(Cnt, Msgs, Q) ->
     case emqx_mqueue:out(Q) of
         {empty, _Q} -> {Msgs, Q};
         {{value, Msg}, Q1} ->
-            dequeue(Cnt-1, [Msg|Msgs], Q1)
+            case emqx_message:is_expired(Msg) of
+                true ->
+                    ok = emqx_metrics:inc('messages.expired'),
+                    dequeue(Cnt-1, Msgs, Q1);
+                false ->
+                    dequeue(Cnt-1, [Msg|Msgs], Q1)
+            end
     end.
 
 batch_n(Inflight) ->
diff --git a/src/emqx_sys_mon.erl b/src/emqx_sys_mon.erl
index f63dd95f6..7d6e5dd6c 100644
--- a/src/emqx_sys_mon.erl
+++ b/src/emqx_sys_mon.erl
@@ -166,7 +166,7 @@ code_change(_OldVsn, State, _Extra) ->
 
 handle_partition_event({partition, {occurred, Node}}) ->
     alarm_handler:set_alarm({partitioned, Node});
-handle_partition_event({partition, {healed, Node}}) ->
+handle_partition_event({partition, {healed, _Node}}) ->
     alarm_handler:clear_alarm(partitioned).
 
 suppress(Key, SuccFun, State = #{events := Events}) ->
diff --git a/src/emqx_ws_connection.erl b/src/emqx_ws_connection.erl
index 9e2f27a49..03e15cce6 100644
--- a/src/emqx_ws_connection.erl
+++ b/src/emqx_ws_connection.erl
@@ -254,6 +254,22 @@ websocket_info({cast, Msg}, State = #ws_connection{chan_state = ChanState}) ->
             stop(Reason, State#ws_connection{chan_state = NChanState})
     end;
 
+websocket_info({incoming, {error, Reason}}, State = #ws_connection{fsm_state = idle}) ->
+    stop({shutdown, Reason}, State);
+
+websocket_info({incoming, {error, Reason}}, State = #ws_connection{fsm_state = connected, chan_state = ChanState}) ->
+    case emqx_channel:handle_out({disconnect, emqx_reason_codes:mqtt_frame_error(Reason)}, ChanState) of
+        {wait_session_expire, _, NChanState} ->
+            ?LOG(debug, "Disconnect and wait for session to expire due to ~p", [Reason]),
+            disconnected(State#ws_connection{chan_state= NChanState});
+        {wait_session_expire, _, OutPackets, NChanState} ->
+            ?LOG(debug, "Disconnect and wait for session to expire due to ~p", [Reason]),
+            disconnected(enqueue(OutPackets, State#ws_connection{chan_state = NChanState}))
+    end;
+
+websocket_info({incoming, {error, _Reason}}, State = #ws_connection{fsm_state = disconnected}) ->
+    reply(State);
+    
 websocket_info({incoming, Packet = ?CONNECT_PACKET(ConnPkt)},
                 State = #ws_connection{fsm_state = idle}) ->
     #mqtt_packet_connect{proto_ver = ProtoVer, properties = Properties} = ConnPkt,
@@ -276,9 +292,7 @@ websocket_info(Deliver = {deliver, _Topic, _Msg},
         {ok, NChanState} ->
             reply(State#ws_connection{chan_state = NChanState});
         {ok, Packets, NChanState} ->
-            reply(enqueue(Packets, State#ws_connection{chan_state = NChanState}));
-        {stop, Reason, NChanState} ->
-            stop(Reason, State#ws_connection{chan_state = NChanState})
+            reply(enqueue(Packets, State#ws_connection{chan_state = NChanState}))
     end;
 
 websocket_info({timeout, TRef, keepalive}, State) when is_reference(TRef) ->
@@ -307,8 +321,7 @@ websocket_info(Info, State = #ws_connection{chan_state = ChanState}) ->
 
 terminate(SockError, _Req, #ws_connection{chan_state  = ChanState,
                                           stop_reason = Reason}) ->
-    ?LOG(debug, "Terminated for ~p, sockerror: ~p",
-         [Reason, SockError]),
+    ?LOG(debug, "Terminated for ~p, sockerror: ~p", [Reason, SockError]),
     emqx_channel:terminate(Reason, ChanState).
 
 %%--------------------------------------------------------------------
@@ -318,6 +331,12 @@ connected(State = #ws_connection{chan_state = ChanState}) ->
     ok = emqx_channel:handle_cast({register, attrs(State), stats(State)}, ChanState),
     reply(State#ws_connection{fsm_state = connected}).
 
+%%--------------------------------------------------------------------
+%% Disconnected callback
+
+disconnected(State) ->
+    reply(State#ws_connection{fsm_state = disconnected}).
+
 %%--------------------------------------------------------------------
 %% Handle timeout
 
@@ -328,6 +347,9 @@ handle_timeout(TRef, Msg, State = #ws_connection{chan_state = ChanState}) ->
         {ok, Packets, NChanState} ->
             NState = State#ws_connection{chan_state = NChanState},
             reply(enqueue(Packets, NState));
+        {wait_session_expire, Reason, NChanState} ->
+            ?LOG(debug, "Disconnect and wait for session to expire due to ~p", [Reason]),
+            disconnected(State#ws_connection{chan_state = NChanState});
         {stop, Reason, NChanState} ->
             stop(Reason, State#ws_connection{chan_state = NChanState})
     end.
@@ -347,29 +369,13 @@ process_incoming(Data, State = #ws_connection{parse_state = ParseState,
             self() ! {incoming, Packet},
             process_incoming(Rest, State#ws_connection{parse_state = NParseState});
         {error, Reason} ->
-            ?LOG(error, "Frame error: ~p", [Reason]),
-            stop(Reason, State)
+            self() ! {incoming, {error, Reason}},
+            {ok, State}
     catch
         error:Reason:Stk ->
-            ?LOG(error, "Parse failed for ~p~nStacktrace:~p~nFrame data: ~p", [Reason, Stk, Data]),
-            Result = 
-                case emqx_channel:info(connected, ChanState) of
-                    undefined ->
-                        emqx_channel:handle_out({connack, emqx_reason_codes:mqtt_frame_error(Reason)}, ChanState);
-                    true ->
-                        emqx_channel:handle_out({disconnect, emqx_reason_codes:mqtt_frame_error(Reason)}, ChanState);
-                    _ ->
-                        ignore
-                end,
-            case Result of
-                {stop, Reason0, OutPackets, NChanState} ->
-                    NState = State#ws_connection{chan_state = NChanState},
-                    stop(Reason0, enqueue(OutPackets, NState));
-                {stop, Reason0, NChanState} ->
-                    stop(Reason0, State#ws_connection{chan_state = NChanState});
-                ignore ->
-                    {ok, State}
-            end
+            ?LOG(error, "~nParse failed for ~p~nStacktrace: ~p~nFrame data: ~p", [Reason, Stk, Data]),
+            self() ! {incoming, {error, Reason}},
+            {ok, State}
     end.
 
 %%--------------------------------------------------------------------
@@ -386,11 +392,17 @@ handle_incoming(Packet = ?PACKET(Type), SuccFun,
         {ok, OutPackets, NChanState} ->
             NState = State#ws_connection{chan_state= NChanState},
             SuccFun(enqueue(OutPackets, NState));
+        {wait_session_expire, Reason, NChanState} ->
+            ?LOG(debug, "Disconnect and wait for session to expire due to ~p", [Reason]),
+            disconnected(State#ws_connection{chan_state = NChanState});
+        {wait_session_expire, Reason, OutPackets, NChanState} ->
+            ?LOG(debug, "Disconnect and wait for session to expire due to ~p", [Reason]),
+            disconnected(enqueue(OutPackets, State#ws_connection{chan_state = NChanState}));
         {stop, Reason, NChanState} ->
-            stop(Reason, State#ws_connection{chan_state= NChanState});
-        {stop, Reason, OutPacket, NChanState} ->
+            stop(Reason, State#ws_connection{chan_state = NChanState});
+        {stop, Reason, OutPackets, NChanState} ->
             NState = State#ws_connection{chan_state= NChanState},
-            stop(Reason, enqueue(OutPacket, NState))
+            stop(Reason, enqueue(OutPackets, NState))
     end.
 
 %%--------------------------------------------------------------------
diff --git a/test/emqx_SUITE.erl b/test/emqx_SUITE.erl
index 96c76b3e6..563683bf1 100644
--- a/test/emqx_SUITE.erl
+++ b/test/emqx_SUITE.erl
@@ -50,6 +50,7 @@ t_emqx_pubsub_api(_) ->
     Payload = <<"Hello World">>,
     Topic1 = <<"mytopic1">>,
     emqx:subscribe(Topic, ClientId),
+    ct:sleep(100),
     ?assertEqual([Topic], emqx:topics()),
     ?assertEqual([self()], emqx:subscribers(Topic)),
     ?assertEqual([{Topic,#{qos => 0,subid => ClientId}}], emqx:subscriptions(self())),
diff --git a/test/emqx_channel_SUITE.erl b/test/emqx_channel_SUITE.erl
index 7d75887c1..e13a76686 100644
--- a/test/emqx_channel_SUITE.erl
+++ b/test/emqx_channel_SUITE.erl
@@ -144,7 +144,7 @@ t_handle_pingreq(_) ->
 t_handle_disconnect(_) ->
     with_channel(
       fun(Channel) ->
-              {stop, {shutdown, normal}, Channel1} = handle_in(?DISCONNECT_PACKET(?RC_SUCCESS), Channel),
+              {wait_session_expire, {shutdown, normal}, Channel1} = handle_in(?DISCONNECT_PACKET(?RC_SUCCESS), Channel),
               ?assertMatch(#{will_msg := undefined}, emqx_channel:info(protocol, Channel1))
       end).
 
diff --git a/test/emqx_client_SUITE.erl b/test/emqx_client_SUITE.erl
index 859406dd8..19557143b 100644
--- a/test/emqx_client_SUITE.erl
+++ b/test/emqx_client_SUITE.erl
@@ -97,6 +97,7 @@ t_cm(_) ->
     ClientId = <<"myclient">>,
     {ok, C} = emqtt:start_link([{client_id, ClientId}]),
     {ok, _} = emqtt:connect(C),
+    ct:sleep(50),
     #{client := #{client_id := ClientId}} = emqx_cm:get_chan_attrs(ClientId),
     emqtt:subscribe(C, <<"mytopic">>, 0),
     ct:sleep(1200),
diff --git a/test/emqx_flapping_SUITE.erl b/test/emqx_flapping_SUITE.erl
index 2fe7c1b24..234fc1950 100644
--- a/test/emqx_flapping_SUITE.erl
+++ b/test/emqx_flapping_SUITE.erl
@@ -22,22 +22,24 @@
 all() -> emqx_ct:all(?MODULE).
 
 init_per_suite(Config) ->
-    prepare_env(),
+    emqx_ct_helpers:boot_modules(all),
+    emqx_ct_helpers:start_apps([], fun set_special_configs/1),
     Config.
 
-prepare_env() ->
+set_special_configs(emqx) ->
     emqx_zone:set_env(external, enable_flapping_detect, true),
     application:set_env(emqx, flapping_detect_policy,
                         #{threshold => 3,
                           duration => 100,
                           banned_interval => 200
-                         }).
+                         });
+set_special_configs(_App) -> ok.
 
 end_per_suite(_Config) ->
+    emqx_ct_helpers:stop_apps([]),
     ok.
 
 t_detect_check(_) ->
-    {ok, _Pid} = emqx_flapping:start_link(),
     ClientInfo = #{zone => external,
                    client_id => <<"clientid">>,
                    peerhost => {127,0,0,1}
diff --git a/test/emqx_msg_expiry_interval_SUITE.erl b/test/emqx_msg_expiry_interval_SUITE.erl
new file mode 100644
index 000000000..0da3efde1
--- /dev/null
+++ b/test/emqx_msg_expiry_interval_SUITE.erl
@@ -0,0 +1,92 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2019 EMQ Technologies Co., Ltd. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
+-module(emqx_msg_expiry_interval_SUITE).
+
+-compile(export_all).
+-compile(nowarn_export_all).
+
+-include_lib("eunit/include/eunit.hrl").
+
+all() -> emqx_ct:all(?MODULE).
+
+init_per_suite(Config) ->
+	emqx_ct_helpers:boot_modules(all),
+    emqx_ct_helpers:start_apps([]),
+    Config.
+
+end_per_suite(_Config) ->
+    emqx_ct_helpers:stop_apps([]).
+
+t_message_expiry_interval_1(_) ->
+	ClientA = message_expiry_interval_init(),
+	[message_expiry_interval_exipred(ClientA, QoS) || QoS <- [0,1,2]].
+
+t_message_expiry_interval_2(_) ->
+	ClientA = message_expiry_interval_init(),
+	[message_expiry_interval_not_exipred(ClientA, QoS) || QoS <- [0,1,2]].
+
+message_expiry_interval_init() ->
+	{ok, ClientA} = emqtt:start_link([{proto_ver,v5}, {client_id, <<"client-a">>}, {clean_start, false},{properties, #{'Session-Expiry-Interval' => 360}}]),
+	{ok, ClientB} = emqtt:start_link([{proto_ver,v5}, {client_id, <<"client-b">>}, {clean_start, false},{properties, #{'Session-Expiry-Interval' => 360}}]),
+	{ok, _} = emqtt:connect(ClientA),
+	{ok, _} = emqtt:connect(ClientB),
+		%% subscribe and disconnect client-b
+	emqtt:subscribe(ClientB, <<"t/a">>, 1),
+	emqtt:stop(ClientB),
+	ClientA.
+
+message_expiry_interval_exipred(ClientA, QoS) ->
+	ct:pal("~p ~p", [?FUNCTION_NAME, QoS]),
+	%% publish to t/a and waiting for the message expired
+	emqtt:publish(ClientA, <<"t/a">>, #{'Message-Expiry-Interval' => 1}, <<"this will be purged in 1s">>, [{qos, QoS}]),
+	ct:sleep(1000),
+
+	%% resume the session for client-b
+	{ok, ClientB1} = emqtt:start_link([{proto_ver,v5}, {client_id, <<"client-b">>}, {clean_start, false},{properties, #{'Session-Expiry-Interval' => 360}}]),
+	{ok, _} = emqtt:connect(ClientB1),
+
+	%% verify client-b could not receive the publish message
+	receive
+		{publish,#{client_pid := ClientB1, topic := <<"t/a">>}} ->
+			ct:fail(should_have_expired)
+	after 300 ->
+		ok
+	end,
+	emqtt:stop(ClientB1).
+
+message_expiry_interval_not_exipred(ClientA, QoS) ->
+	ct:pal("~p ~p", [?FUNCTION_NAME, QoS]),
+	%% publish to t/a
+	emqtt:publish(ClientA, <<"t/a">>, #{'Message-Expiry-Interval' => 20}, <<"this will be purged in 1s">>, [{qos, QoS}]),
+
+	%% wait for 1s and then resume the session for client-b, the message should not expires
+	%% as Message-Expiry-Interval = 20s
+	ct:sleep(1000),
+	{ok, ClientB1} = emqtt:start_link([{proto_ver,v5}, {client_id, <<"client-b">>}, {clean_start, false},{properties, #{'Session-Expiry-Interval' => 360}}]),
+	{ok, _} = emqtt:connect(ClientB1),
+
+	%% verify client-b could receive the publish message and the Message-Expiry-Interval is set
+	receive
+		{publish,#{client_pid := ClientB1, topic := <<"t/a">>,
+					properties := #{'Message-Expiry-Interval' := MsgExpItvl}}}
+			when MsgExpItvl < 20 -> ok;
+		{publish, _} = Msg ->
+			ct:fail({incorrect_publish, Msg})
+	after 300 ->
+		ct:fail(no_publish_received)
+	end,
+	emqtt:stop(ClientB1).