diff --git a/.cproject b/.cproject
index 3966019..62eba26 100644
--- a/.cproject
+++ b/.cproject
@@ -133,7 +133,7 @@
                     					
                     <sourceEntries>
                         						
-                        <entry excluding="MQTTSNGateway/src/linux/udp|MQTTSNGateway/GatewayTester|MQTTSNClient|MQTTSNGateway/src/MQTTSNGWProxy.cpp|MQTTSNPacket/test|MQTTSNPacket/samples|MQTTSNGateway/src/mainLogmonitor.cpp|MQTTSNGateway/src/linux/xbee|MQTTSNGateway/GatewayTester/samples/mainTemplate.cpp|MQTTSNGateway/src/tests|MQTTSNGateway/src/tests/mainTestProcessFramework.cpp|ClientPubQoS-1|MQTTSNGateway/GatewayTester/samples/mainOTA.cpp" flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name=""/>
+                        <entry excluding="MQTTSNGateway/src/linux/udp6|MQTTSNGateway/GatewayTester|MQTTSNClient|MQTTSNGateway/src/MQTTSNGWProxy.cpp|MQTTSNPacket/test|MQTTSNPacket/samples|MQTTSNGateway/src/mainLogmonitor.cpp|MQTTSNGateway/src/linux/xbee|MQTTSNGateway/GatewayTester/samples/mainTemplate.cpp|MQTTSNGateway/src/tests|MQTTSNGateway/src/tests/mainTestProcessFramework.cpp|ClientPubQoS-1|MQTTSNGateway/GatewayTester/samples/mainOTA.cpp" flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name=""/>
                         					
                     </sourceEntries>
                     				
@@ -277,7 +277,7 @@
                         						
                         <entry excluding="MQTTSNGWProxy.cpp|mainLogmonitor.cpp|tests|tests/mainTestProcessFramework.cpp|linux|linux/udp" flags="VALUE_WORKSPACE_PATH" kind="sourcePath" name="MQTTSNGateway/src"/>
                         						
-                        <entry excluding="udp|xbee" flags="VALUE_WORKSPACE_PATH" kind="sourcePath" name="MQTTSNGateway/src/linux"/>
+                        <entry excluding="udp6|xbee" flags="VALUE_WORKSPACE_PATH" kind="sourcePath" name="MQTTSNGateway/src/linux"/>
                         						
                         <entry flags="VALUE_WORKSPACE_PATH" kind="sourcePath" name="MQTTSNPacket/src"/>
                         					
diff --git a/MQTTSNGateway/GatewayTester/samples/mainTest.cpp b/MQTTSNGateway/GatewayTester/samples/mainTest.cpp
index 06aa565..934a419 100644
--- a/MQTTSNGateway/GatewayTester/samples/mainTest.cpp
+++ b/MQTTSNGateway/GatewayTester/samples/mainTest.cpp
@@ -138,7 +138,7 @@ void publishTopic1(void)
 	PUBLISH(topic1,(uint8_t*)payload, strlen(payload), QoS0);
 }
 
-void subscribeTopic2(void)
+void subscribeTopic10(void)
 {
 	SUBSCRIBE(10, on_Topic02, QoS1);
 }
@@ -190,7 +190,7 @@ TEST_LIST = {// e.g. TEST( Label, Test),
             TEST("Step0:Subscribe predef topic1",     subscribePredefTopic1),
 			 TEST("Step1:Publish topic1",     publishTopic1),
 			 TEST("Step2:Publish topic2",     publishTopic2),
-			 TEST("Step3:Subscribe topic2",   subscribeTopic2),
+			 TEST("Step3:Subscribe PreDefined topic10. ID is not defined.",   subscribeTopic10),
 			 TEST("Step4:Publish topic2",     publishTopic2),
 			 TEST("Step5:Unsubscribe topic2", unsubscribe),
 			 TEST("Step6:Publish topic2",     publishTopic2),
diff --git a/MQTTSNGateway/gateway.conf b/MQTTSNGateway/gateway.conf
index c06853b..d01903a 100644
--- a/MQTTSNGateway/gateway.conf
+++ b/MQTTSNGateway/gateway.conf
@@ -1,5 +1,5 @@
 #**************************************************************************
-# Copyright (c) 2016-2018, Tomoaki Yamaguchi
+# Copyright (c) 2016-2019, Tomoaki Yamaguchi
 #
 # All rights reserved. This program and the accompanying materials
 # are made available under the terms of the Eclipse Public License v1.0
@@ -14,7 +14,7 @@
 # config file of MQTT-SN Gateway
 #
 
-BrokerName=iot.eclipse.org
+BrokerName=mqtt.eclipse.org
 BrokerPortNo=1883
 BrokerSecurePortNo=8883
 
@@ -50,6 +50,12 @@ GatewayPortNo=10000
 MulticastIP=225.1.1.1
 MulticastPortNo=1883
 
+# UDP6
+GatewayUDP6Bind=FFFF:FFFE::1 
+GatewayUDP6Port=10000
+GatewayUDP6Broadcast=FF02::1
+GatewayUDP6If=wpan0
+
 # XBee
 Baudrate=38400
 SerialDevice=/dev/ttyUSB0
diff --git a/MQTTSNGateway/src/MQTTSNGWClientList.cpp b/MQTTSNGateway/src/MQTTSNGWClientList.cpp
index e4e0bb9..5452765 100644
--- a/MQTTSNGateway/src/MQTTSNGWClientList.cpp
+++ b/MQTTSNGateway/src/MQTTSNGWClientList.cpp
@@ -416,9 +416,9 @@ Client* ClientList::createClient(SensorNetAddress* addr, MQTTSNString* clientId,
 
 Client* ClientList::createPredefinedTopic( MQTTSNString* clientId, string topicName, uint16_t topicId, bool aggregate)
 {
-	if ( clientId->cstring == common_topic )
+	if ( strcmp(clientId->cstring, common_topic) == 0 )
 	{
-		_gateway->getTopics()->add((const char*)topicName.c_str(), topicId);
+		theGateway->getTopics()->add((const char*)topicName.c_str(), topicId);
 		return 0;
 	}
 	else
diff --git a/MQTTSNGateway/src/MQTTSNGWClientSendTask.cpp b/MQTTSNGateway/src/MQTTSNGWClientSendTask.cpp
index fc8c412..eaa6e68 100644
--- a/MQTTSNGateway/src/MQTTSNGWClientSendTask.cpp
+++ b/MQTTSNGateway/src/MQTTSNGWClientSendTask.cpp
@@ -18,6 +18,7 @@
 #include "MQTTSNGateway.h"
 #include "MQTTSNGWEncapsulatedPacket.h"
 #include "MQTTSNGWQoSm1Proxy.h"
+#include <errno.h>
 
 using namespace MQTTSNGW;
 using namespace std;
@@ -75,8 +76,8 @@ void ClientSendTask::run()
 
 		if ( rc < 0 )
 		{
-			WRITELOG("%s ClientSendTask can't send a packet to the client %s%s.\n",
-				ERRMSG_HEADER, (client ? (const char*)client->getClientId() : UNKNOWNCL ), ERRMSG_FOOTER);
+			WRITELOG("%s ClientSendTask can't send a packet to the client %s. Error=%d%s\n",
+				ERRMSG_HEADER, (client ? (const char*)client->getClientId() : UNKNOWNCL ), errno, ERRMSG_FOOTER);
 		}
 		delete ev;
 	}
diff --git a/MQTTSNGateway/src/MQTTSNGWSubscribeHandler.cpp b/MQTTSNGateway/src/MQTTSNGWSubscribeHandler.cpp
index cd4bc30..dceb864 100644
--- a/MQTTSNGateway/src/MQTTSNGWSubscribeHandler.cpp
+++ b/MQTTSNGateway/src/MQTTSNGWSubscribeHandler.cpp
@@ -60,25 +60,22 @@ MQTTGWPacket* MQTTSNSubscribeHandler::handleSubscribe(Client* client, MQTTSNPack
     {
         topic = client->getTopics()->getTopicById(&topicFilter);
 
-
-        if ( topic )
-        {
-            topicId = topic->getTopicId();
-            subscribe = new MQTTGWPacket();
-            subscribe->setSUBSCRIBE((char*)topic->getTopicName()->c_str(), (uint8_t)qos, (uint16_t)msgId);
-        }
-        else
+        if ( !topic )
         {
         	topic = _gateway->getTopics()->getTopicById(&topicFilter);
-        	if ( !topic )
-        	{
+			if ( topic )
+			{
 				topic = client->getTopics()->add(topic->getTopicName()->c_str(), topic->getTopicId());
 			}
-        	else
-        	{
-        		goto RespExit;
-        	}
+			else
+			{
+				goto RespExit;
+			}
         }
+        topicId = topic->getTopicId();
+        subscribe = new MQTTGWPacket();
+        subscribe->setSUBSCRIBE((char*)topic->getTopicName()->c_str(), (uint8_t)qos, (uint16_t)msgId);
+
     }
     else if (topicFilter.type == MQTTSN_TOPIC_TYPE_NORMAL)
     {
@@ -148,7 +145,6 @@ MQTTGWPacket* MQTTSNSubscribeHandler::handleUnsubscribe(Client* client, MQTTSNPa
 	    return nullptr;
     }
 
-	Topic* topic = client->getTopics()->getTopicById(&topicFilter);
 
 	if (topicFilter.type == MQTTSN_TOPIC_TYPE_SHORT)
 	{
@@ -161,6 +157,17 @@ MQTTGWPacket* MQTTSNSubscribeHandler::handleUnsubscribe(Client* client, MQTTSNPa
 	}
 	else
 	{
+		Topic* topic = nullptr;
+
+		if (topicFilter.type == MQTTSN_TOPIC_TYPE_PREDEFINED)
+		{
+			topic = client->getTopics()->getTopicById(&topicFilter);
+		}
+		else
+		{
+			topic = client->getTopics()->getTopicByName(&topicFilter);
+		}
+
 	    if ( topic == nullptr )
         {
             MQTTSNPacket* sUnsuback = new MQTTSNPacket();