diff --git a/app/modules/mqtt.c b/app/modules/mqtt.c
index 78a41f18..2b6a35b3 100644
--- a/app/modules/mqtt.c
+++ b/app/modules/mqtt.c
@@ -75,7 +75,7 @@ typedef struct lmqtt_userdata
   tConnState connState;
 }lmqtt_userdata;
 
-static void socket_connect(struct espconn *pesp_conn);
+static sint8 socket_connect(struct espconn *pesp_conn);
 static void mqtt_socket_reconnected(void *arg, sint8_t err);
 static void mqtt_socket_connected(void *arg);
 
@@ -397,12 +397,12 @@ READPACKET:
 #ifdef CLIENT_SSL_ENABLE
     if( mud->secure )
     {
-      espconn_secure_sent( pesp_conn, node->msg.data, node->msg.length );
+      espconn_secure_send( pesp_conn, node->msg.data, node->msg.length );
     }
     else
 #endif
     {
-      espconn_sent( pesp_conn, node->msg.data, node->msg.length );
+      espconn_send( pesp_conn, node->msg.data, node->msg.length );
     }
   }
   NODE_DBG("receive, queue size: %d\n", msg_size(&(mud->mqtt_state.pending_msg_q)));
@@ -479,12 +479,12 @@ static void mqtt_socket_connected(void *arg)
 #ifdef CLIENT_SSL_ENABLE
   if(mud->secure)
   {
-    espconn_secure_sent(pesp_conn, temp_msg->data, temp_msg->length);
+    espconn_secure_send(pesp_conn, temp_msg->data, temp_msg->length);
   }
   else
 #endif
   {
-    espconn_sent(pesp_conn, temp_msg->data, temp_msg->length);
+    espconn_send(pesp_conn, temp_msg->data, temp_msg->length);
   }
   mud->keep_alive_tick = 0;
 
@@ -547,12 +547,12 @@ void mqtt_socket_timer(void *arg)
 #ifdef CLIENT_SSL_ENABLE
       if(mud->secure)
       {
-        espconn_secure_sent(mud->pesp_conn, pending_msg->msg.data, pending_msg->msg.length);
+        espconn_secure_send(mud->pesp_conn, pending_msg->msg.data, pending_msg->msg.length);
       }
       else
 #endif
       {
-        espconn_sent(mud->pesp_conn, pending_msg->msg.data, pending_msg->msg.length);
+        espconn_send(mud->pesp_conn, pending_msg->msg.data, pending_msg->msg.length);
       }
       mud->keep_alive_tick = 0;
       NODE_DBG("id: %d - qos: %d, length: %d\n", pending_msg->msg_id, pending_msg->publish_qos, pending_msg->msg.length);
@@ -571,12 +571,12 @@ void mqtt_socket_timer(void *arg)
 #ifdef CLIENT_SSL_ENABLE
         if(mud->secure)
         {
-          espconn_secure_sent(mud->pesp_conn, temp_msg->data, temp_msg->length);
+          espconn_secure_send(mud->pesp_conn, temp_msg->data, temp_msg->length);
         }
         else
 #endif
         {
-          espconn_sent(mud->pesp_conn, temp_msg->data, temp_msg->length);
+          espconn_send(mud->pesp_conn, temp_msg->data, temp_msg->length);
         }
         mud->keep_alive_tick = 0;
       }
@@ -805,43 +805,55 @@ static int mqtt_delete( lua_State* L )
   return 0;
 }
 
-static void socket_connect(struct espconn *pesp_conn)
+static sint8 socket_connect(struct espconn *pesp_conn)
 {
   NODE_DBG("enter socket_connect.\n");
+  sint8 espconn_status;
+
   if(pesp_conn == NULL)
-    return;
+    return ESPCONN_CONN;
   lmqtt_userdata *mud = (lmqtt_userdata *)pesp_conn->reverse;
   if(mud == NULL)
-    return;
+    return ESPCONN_ARG;
 
   mud->event_timeout = MQTT_CONNECT_TIMEOUT;
   mud->connState = MQTT_INIT;
 #ifdef CLIENT_SSL_ENABLE
   if(mud->secure)
   {
-    espconn_secure_connect(pesp_conn);
+    espconn_status = espconn_secure_connect(pesp_conn);
   }
   else
 #endif
   {
-    espconn_connect(pesp_conn);
+    espconn_status = espconn_connect(pesp_conn);
   }
 
   os_timer_arm(&mud->mqttTimer, 1000, 1);
 
   NODE_DBG("leave socket_connect.\n");
+
+  return espconn_status;
 }
 
-static void socket_dns_found(const char *name, ip_addr_t *ipaddr, void *arg);
+static sint8 socket_dns_found(const char *name, ip_addr_t *ipaddr, void *arg);
 static int dns_reconn_count = 0;
 static ip_addr_t host_ip; // for dns
-static void socket_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
+
+/* wrapper for using socket_dns_found() as callback function */
+static void socket_dns_foundcb(const char *name, ip_addr_t *ipaddr, void *arg)
+{
+  socket_dns_found(name, ipaddr, arg);
+}
+
+static sint8 socket_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
 {
   NODE_DBG("enter socket_dns_found.\n");
+  sint8 espconn_status = ESPCONN_OK;
   struct espconn *pesp_conn = arg;
   if(pesp_conn == NULL){
     NODE_DBG("pesp_conn null.\n");
-    return;
+    return -1;
   }
 
   if(ipaddr == NULL)
@@ -851,12 +863,11 @@ static void socket_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
       NODE_ERR( "DNS Fail!\n" );
       // Note: should delete the pesp_conn or unref self_ref here.
       mqtt_socket_disconnected(arg);   // although not connected, but fire disconnect callback to release every thing.
-      return;
+      return -1;
     }
     NODE_ERR( "DNS retry %d!\n", dns_reconn_count );
     host_ip.addr = 0;
-    espconn_gethostbyname(pesp_conn, name, &host_ip, socket_dns_found);
-    return;
+    return espconn_gethostbyname(pesp_conn, name, &host_ip, socket_dns_foundcb);
   }
 
   // ipaddr->addr is a uint32_t ip
@@ -867,9 +878,11 @@ static void socket_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
     NODE_DBG("TCP ip is set: ");
     NODE_DBG(IPSTR, IP2STR(&(ipaddr->addr)));
     NODE_DBG("\n");
-    socket_connect(pesp_conn);
+    espconn_status = socket_connect(pesp_conn);
   }
   NODE_DBG("leave socket_dns_found.\n");
+
+  return espconn_status;
 }
 
 // Lua: mqtt:connect( host, port, secure, auto_reconnect, function(client) )
@@ -884,6 +897,7 @@ static int mqtt_socket_connect( lua_State* L )
   int stack = 1;
   unsigned secure = 0, auto_reconnect = 0;
   int top = lua_gettop(L);
+  sint8 espconn_status;
 
   mud = (lmqtt_userdata *)luaL_checkudata(L, stack, "mqtt.socket");
   luaL_argcheck(L, mud, stack, "mqtt.socket expected");
@@ -905,21 +919,21 @@ static int mqtt_socket_connect( lua_State* L )
   }
 
   struct espconn *pesp_conn = NULL;
-	pesp_conn = mud->pesp_conn = (struct espconn *)c_zalloc(sizeof(struct espconn));
-	if(!pesp_conn)
-		return luaL_error(L, "not enough memory");
+  pesp_conn = mud->pesp_conn = (struct espconn *)c_zalloc(sizeof(struct espconn));
+  if(!pesp_conn)
+    return luaL_error(L, "not enough memory");
 
-	pesp_conn->proto.udp = NULL;
-	pesp_conn->proto.tcp = (esp_tcp *)c_zalloc(sizeof(esp_tcp));
-	if(!pesp_conn->proto.tcp){
-		c_free(pesp_conn);
-		pesp_conn = mud->pesp_conn = NULL;
-		return luaL_error(L, "not enough memory");
-	}
-	// reverse is for the callback function
-	pesp_conn->reverse = mud;
-	pesp_conn->type = ESPCONN_TCP;
-	pesp_conn->state = ESPCONN_NONE;
+  pesp_conn->proto.udp = NULL;
+  pesp_conn->proto.tcp = (esp_tcp *)c_zalloc(sizeof(esp_tcp));
+  if(!pesp_conn->proto.tcp){
+    c_free(pesp_conn);
+    pesp_conn = mud->pesp_conn = NULL;
+    return luaL_error(L, "not enough memory");
+  }
+  // reverse is for the callback function
+  pesp_conn->reverse = mud;
+  pesp_conn->type = ESPCONN_TCP;
+  pesp_conn->state = ESPCONN_NONE;
   mud->connected = false;
 
   if( (stack<=top) && lua_isstring(L,stack) )   // deal with the domain string
@@ -993,8 +1007,8 @@ static int mqtt_socket_connect( lua_State* L )
     luaL_unref(L, LUA_REGISTRYINDEX, mud->self_ref);
   mud->self_ref = luaL_ref(L, LUA_REGISTRYINDEX);
 
-  espconn_regist_connectcb(pesp_conn, mqtt_socket_connected);
-  espconn_regist_reconcb(pesp_conn, mqtt_socket_reconnected);
+  espconn_status = espconn_regist_connectcb(pesp_conn, mqtt_socket_connected);
+  espconn_status |= espconn_regist_reconcb(pesp_conn, mqtt_socket_reconnected);
 
   os_timer_disarm(&mud->mqttTimer);
   os_timer_setfn(&mud->mqttTimer, (os_timer_func_t *)mqtt_socket_timer, mud);
@@ -1004,17 +1018,23 @@ static int mqtt_socket_connect( lua_State* L )
   {
     host_ip.addr = 0;
     dns_reconn_count = 0;
-    if(ESPCONN_OK == espconn_gethostbyname(pesp_conn, domain, &host_ip, socket_dns_found)){
-      socket_dns_found(domain, &host_ip, pesp_conn);  // ip is returned in host_ip.
+    if(ESPCONN_OK == espconn_gethostbyname(pesp_conn, domain, &host_ip, socket_dns_foundcb)){
+      espconn_status |= socket_dns_found(domain, &host_ip, pesp_conn);  // ip is returned in host_ip.
     }
   }
   else
   {
-    socket_connect(pesp_conn);
+    espconn_status |= socket_connect(pesp_conn);
   }
 
   NODE_DBG("leave mqtt_socket_connect.\n");
-  return 0;
+
+  if (espconn_status == ESPCONN_OK) {
+    lua_pushboolean(L, 1);
+  } else {
+    lua_pushboolean(L, 0);
+  }
+  return 1;
 }
 
 // Lua: mqtt:close()
@@ -1027,37 +1047,44 @@ static int mqtt_socket_close( lua_State* L )
 
   mud = (lmqtt_userdata *)luaL_checkudata(L, 1, "mqtt.socket");
   luaL_argcheck(L, mud, 1, "mqtt.socket expected");
-  if(mud == NULL)
-    return 0;
-
-  if(mud->pesp_conn == NULL)
-    return 0;
+  if (mud == NULL || mud->pesp_conn == NULL) {
+    lua_pushboolean(L, 0);
+    return 1;
+  }
 
   // Send disconnect message
   mqtt_message_t* temp_msg = mqtt_msg_disconnect(&mud->mqtt_state.mqtt_connection);
   NODE_DBG("Send MQTT disconnect infomation, data len: %d, d[0]=%d \r\n", temp_msg->length,  temp_msg->data[0]);
+
+  sint8 espconn_status;
 #ifdef CLIENT_SSL_ENABLE
   if(mud->secure)
-    espconn_secure_sent(mud->pesp_conn, temp_msg->data, temp_msg->length);
+    espconn_status = espconn_secure_send(mud->pesp_conn, temp_msg->data, temp_msg->length);
   else
 #endif
-    espconn_sent(mud->pesp_conn, temp_msg->data, temp_msg->length);
+    espconn_status = espconn_send(mud->pesp_conn, temp_msg->data, temp_msg->length);
 
   mud->mqtt_state.auto_reconnect = 0;   // stop auto reconnect.
 
 #ifdef CLIENT_SSL_ENABLE
   if(mud->secure){
     if(mud->pesp_conn->proto.tcp->remote_port || mud->pesp_conn->proto.tcp->local_port)
-      espconn_secure_disconnect(mud->pesp_conn);
+      espconn_status |= espconn_secure_disconnect(mud->pesp_conn);
   }
   else
 #endif
   {
     if(mud->pesp_conn->proto.tcp->remote_port || mud->pesp_conn->proto.tcp->local_port)
-      espconn_disconnect(mud->pesp_conn);
+      espconn_status |= espconn_disconnect(mud->pesp_conn);
   }
   NODE_DBG("leave mqtt_socket_close.\n");
-  return 0;
+
+  if (espconn_status == ESPCONN_OK) {
+    lua_pushboolean(L, 1);
+  } else {
+    lua_pushboolean(L, 0);
+  }
+  return 1;
 }
 
 // Lua: mqtt:on( "method", function() )
@@ -1103,17 +1130,17 @@ static int mqtt_socket_on( lua_State* L )
 
 // Lua: bool = mqtt:subscribe(topic, qos, function())
 static int mqtt_socket_subscribe( lua_State* L ) {
-	NODE_DBG("enter mqtt_socket_subscribe.\n");
+  NODE_DBG("enter mqtt_socket_subscribe.\n");
 
-	uint8_t stack = 1, qos = 0;
+  uint8_t stack = 1, qos = 0;
   uint16_t msg_id = 0;
-	const char *topic;
-	size_t il;
-	lmqtt_userdata *mud;
+  const char *topic;
+  size_t il;
+  lmqtt_userdata *mud;
 
-	mud = (lmqtt_userdata *) luaL_checkudata( L, stack, "mqtt.socket" );
-	luaL_argcheck( L, mud, stack, "mqtt.socket expected" );
-	stack++;
+  mud = (lmqtt_userdata *) luaL_checkudata( L, stack, "mqtt.socket" );
+  luaL_argcheck( L, mud, stack, "mqtt.socket expected" );
+  stack++;
 
   if(mud==NULL){
     NODE_DBG("userdata is nil.\n");
@@ -1127,8 +1154,8 @@ static int mqtt_socket_subscribe( lua_State* L ) {
     return 1;
   }
 
-	if(!mud->connected){
-		luaL_error( L, "not connected" );
+  if(!mud->connected){
+    luaL_error( L, "not connected" );
     lua_pushboolean(L, 0);
     return 1;
   }
@@ -1137,53 +1164,60 @@ static int mqtt_socket_subscribe( lua_State* L ) {
   mqtt_msg_init(&mud->mqtt_state.mqtt_connection, temp_buffer, MQTT_BUF_SIZE);
   mqtt_message_t *temp_msg = NULL;
 
-	if( lua_istable( L, stack ) ) {
-		NODE_DBG("subscribe table\n");
-		lua_pushnil( L ); /* first key */
+  if( lua_istable( L, stack ) ) {
+    NODE_DBG("subscribe table\n");
+    lua_pushnil( L ); /* first key */
 
     uint8_t temp_buf[MQTT_BUF_SIZE];
     uint32_t temp_pos = 0;
+    uint8_t overflow = 0;
 
-		while( lua_next( L, stack ) != 0 ) {
-			topic = luaL_checkstring( L, -2 );
-			qos = luaL_checkinteger( L, -1 );
+    while( lua_next( L, stack ) != 0 ) {
+      topic = luaL_checkstring( L, -2 );
+      qos = luaL_checkinteger( L, -1 );
 
-			temp_msg = mqtt_msg_subscribe( &mud->mqtt_state.mqtt_connection, topic, qos, &msg_id );
-			NODE_DBG("topic: %s - qos: %d, length: %d\n", topic, qos, temp_msg->length);
+      temp_msg = mqtt_msg_subscribe( &mud->mqtt_state.mqtt_connection, topic, qos, &msg_id );
+      NODE_DBG("topic: %s - qos: %d, length: %d\n", topic, qos, temp_msg->length);
 
       if (temp_pos + temp_msg->length > MQTT_BUF_SIZE){
         lua_pop(L, 1);
+        overflow = 1;
         break;  // too long message for the outbuffer.
       }
       c_memcpy( temp_buf + temp_pos, temp_msg->data, temp_msg->length );
       temp_pos += temp_msg->length;
 
-			lua_pop( L, 1 );
-		}
+      lua_pop( L, 1 );
+    }
 
     if (temp_pos == 0){
       luaL_error( L, "invalid data" );
       lua_pushboolean(L, 0);
       return 1;
     }
-
-    c_memcpy( temp_buffer, temp_buf, temp_pos );
-		temp_msg->data = temp_buffer;
-		temp_msg->length = temp_pos;
-		stack++;
-	} else {
-		NODE_DBG("subscribe string\n");
-		topic = luaL_checklstring( L, stack, &il );
-		stack++;
-		if( topic == NULL ){
-			luaL_error( L, "need topic name" );
+    if (overflow != 0){
+      luaL_error( L, "buffer overflow, can't enqueue all subscriptions" );
       lua_pushboolean(L, 0);
       return 1;
     }
-		qos = luaL_checkinteger( L, stack );
-		temp_msg = mqtt_msg_subscribe( &mud->mqtt_state.mqtt_connection, topic, qos, &msg_id );
-		stack++;
-	}
+
+    c_memcpy( temp_buffer, temp_buf, temp_pos );
+    temp_msg->data = temp_buffer;
+    temp_msg->length = temp_pos;
+    stack++;
+  } else {
+    NODE_DBG("subscribe string\n");
+    topic = luaL_checklstring( L, stack, &il );
+    stack++;
+    if( topic == NULL ){
+      luaL_error( L, "need topic name" );
+      lua_pushboolean(L, 0);
+      return 1;
+    }
+    qos = luaL_checkinteger( L, stack );
+    temp_msg = mqtt_msg_subscribe( &mud->mqtt_state.mqtt_connection, topic, qos, &msg_id );
+    stack++;
+  }
 
   if( lua_type( L, stack ) == LUA_TFUNCTION || lua_type( L, stack ) == LUA_TLIGHTFUNCTION ) {    // TODO: this will overwrite the previous one.
     lua_pushvalue( L, stack );  // copy argument (func) to the top of stack
@@ -1193,34 +1227,36 @@ static int mqtt_socket_subscribe( lua_State* L ) {
   }
 
   msg_queue_t *node = msg_enqueue( &(mud->mqtt_state.pending_msg_q), temp_msg,
-                            msg_id, MQTT_MSG_TYPE_SUBSCRIBE, (int)mqtt_get_qos(temp_msg->data) );
+                                   msg_id, MQTT_MSG_TYPE_SUBSCRIBE, (int)mqtt_get_qos(temp_msg->data) );
 
   NODE_DBG("topic: %s - id: %d - qos: %d, length: %d\n", topic, node->msg_id, node->publish_qos, node->msg.length);
 
+  sint8 espconn_status = ESPCONN_IF;
+
   if(node && (1==msg_size(&(mud->mqtt_state.pending_msg_q))) && mud->event_timeout == 0){
-  	mud->event_timeout = MQTT_SEND_TIMEOUT;
-  	NODE_DBG("Sent: %d\n", node->msg.length);
+    mud->event_timeout = MQTT_SEND_TIMEOUT;
+    NODE_DBG("Sent: %d\n", node->msg.length);
 #ifdef CLIENT_SSL_ENABLE
-  	if( mud->secure )
-        {
-          espconn_secure_sent( mud->pesp_conn, node->msg.data, node->msg.length );
-        }
-  	else
+    if( mud->secure )
+    {
+      espconn_status = espconn_secure_send( mud->pesp_conn, node->msg.data, node->msg.length );
+    }
+    else
 #endif
-        {
-          espconn_sent( mud->pesp_conn, node->msg.data, node->msg.length );
-        }
+    {
+      espconn_status = espconn_send( mud->pesp_conn, node->msg.data, node->msg.length );
+    }
     mud->keep_alive_tick = 0;
   }
 
-  if(!node){
+  if(!node || espconn_status != ESPCONN_OK){
     lua_pushboolean(L, 0);
   } else {
     lua_pushboolean(L, 1);  // enqueued succeed.
   }
   NODE_DBG("subscribe, queue size: %d\n", msg_size(&(mud->mqtt_state.pending_msg_q)));
   NODE_DBG("leave mqtt_socket_subscribe.\n");
-	return 1;
+  return 1;
 }
 
 // Lua: bool = mqtt:publish( topic, payload, qos, retain, function() )
@@ -1232,6 +1268,7 @@ static int mqtt_socket_publish( lua_State* L )
   size_t l;
   uint8_t stack = 1;
   uint16_t msg_id = 0;
+
   mud = (lmqtt_userdata *)luaL_checkudata(L, stack, "mqtt.socket");
   luaL_argcheck(L, mud, stack, "mqtt.socket expected");
   stack++;
@@ -1285,23 +1322,25 @@ static int mqtt_socket_publish( lua_State* L )
   msg_queue_t *node = msg_enqueue(&(mud->mqtt_state.pending_msg_q), temp_msg,
                       msg_id, MQTT_MSG_TYPE_PUBLISH, (int)qos );
 
+  sint8 espconn_status = ESPCONN_IF;
+
   if(node && (1==msg_size(&(mud->mqtt_state.pending_msg_q))) && mud->event_timeout == 0){
     mud->event_timeout = MQTT_SEND_TIMEOUT;
     NODE_DBG("Sent: %d\n", node->msg.length);
 #ifdef CLIENT_SSL_ENABLE
     if( mud->secure )
     {
-      espconn_secure_sent( mud->pesp_conn, node->msg.data, node->msg.length );
+      espconn_status = espconn_secure_send( mud->pesp_conn, node->msg.data, node->msg.length );
     }
     else
 #endif
     {
-      espconn_sent( mud->pesp_conn, node->msg.data, node->msg.length );
+      espconn_status = espconn_send( mud->pesp_conn, node->msg.data, node->msg.length );
     }
     mud->keep_alive_tick = 0;
   }
 
-  if(!node){
+  if(!node || espconn_status != ESPCONN_OK){
     lua_pushboolean(L, 0);
   } else {
     lua_pushboolean(L, 1);  // enqueued succeed.
diff --git a/docs/en/modules/mqtt.md b/docs/en/modules/mqtt.md
index e8e06969..1d07cd64 100644
--- a/docs/en/modules/mqtt.md
+++ b/docs/en/modules/mqtt.md
@@ -71,7 +71,7 @@ Closes connection to the broker.
 none
 
 #### Returns
-`nil`
+`true` on success, `false` otherwise
 
 ## mqtt.client:connect()
 
@@ -88,7 +88,7 @@ Connects to the broker specified by the given host, port, and secure options.
 - `function(client)` call back function for when the connection was established
 
 #### Returns
-`nil`
+`true` on success, `false` otherwise
 
 ## mqtt.client:lwt()
 
@@ -135,7 +135,7 @@ Publishes a message.
 - `function(client)` optional callback fired when PUBACK received
 
 #### Returns
-`nil`
+`true` on success, `false` otherwise
 
 ## mqtt.client:subscribe()
 
@@ -143,11 +143,21 @@ Subscribes to one or several topics.
 
 #### Syntax
 `mqtt:subscribe(topic, qos[, function(client, topic, message)])`
+`mqtt:subscribe(table[, function(client, topic, message)])`
 
 #### Parameters
 - `topic` a [topic string](http://www.hivemq.com/blog/mqtt-essentials-part-5-mqtt-topics-best-practices)
 - `qos` QoS subscription level, default 0
+- `table` array of 'topic, qos' pairs to subscribe to
 - `function(client, topic, message)` optional callback fired when message received
 
 #### Returns
-`nil`
+`true` on success, `false` otherwise
+
+#### Example
+```lua
+-- subscribe topic with qos = 0
+m:subscribe("/topic",0, function(conn) print("subscribe success") end)
+
+-- or subscribe multiple topic (topic/0, qos = 0; topic/1, qos = 1; topic2 , qos = 2)
+m:subscribe({["topic/0"]=0,["topic/1"]=1,topic2=2}, function(conn) print("subscribe success") end)