diff --git a/src/Clients.h b/src/Clients.h
index 46ac1d4d..e93bd508 100644
--- a/src/Clients.h
+++ b/src/Clients.h
@@ -182,6 +182,7 @@ typedef struct
 	void* phandle;  /* the persistence handle */
 	MQTTClient_persistence* persistence; /* a persistence implementation */
 	void* context; /* calling context - used when calling disconnect_internal */
+	int MQTTVersion;
 #if defined(OPENSSL)
 	MQTTClient_SSLOptions *sslopts;
 	SSL_SESSION* session;    /***< SSL session pointer for fast handhake */
diff --git a/src/MQTTAsync.c b/src/MQTTAsync.c
index 2a508b15..82b1479c 100644
--- a/src/MQTTAsync.c
+++ b/src/MQTTAsync.c
@@ -249,7 +249,7 @@ typedef struct
 			int serverURIcount;
 			char** serverURIs;
 			int currentURI;
-			int MQTTVersion;
+			int MQTTVersion; /**< current MQTT version being used to connect */
 		} conn;
 	} details;
 } MQTTAsync_command;
@@ -336,13 +336,13 @@ void MQTTAsync_unlock_mutex(mutex_type amutex)
 }
 
 
-int MQTTAsync_checkConn(MQTTAsync_command* command)
+int MQTTAsync_checkConn(MQTTAsync_command* command, MQTTAsyncs* client)
 {
   int rc;
 
   FUNC_ENTRY;
   rc = command->details.conn.currentURI < command->details.conn.serverURIcount ||
-      command->details.conn.MQTTVersion == 4;
+      (command->details.conn.MQTTVersion == 4 && client->c->MQTTVersion == MQTTVERSION_DEFAULT);
   FUNC_EXIT_RC(rc);
   return rc;
 }
@@ -977,11 +977,16 @@ void MQTTAsync_processCommand()
 
 			if (command->command.details.conn.serverURIcount > 0)
 			{
-				if (command->command.details.conn.MQTTVersion == 3)
+				if (command->client->c->MQTTVersion == MQTTVERSION_DEFAULT)
 				{
+					if (command->command.details.conn.MQTTVersion == 3)
+					{
+						command->command.details.conn.currentURI++;
+						command->command.details.conn.MQTTVersion = 4;
+					} 
+				}
+				else
 					command->command.details.conn.currentURI++;
-					command->command.details.conn.MQTTVersion = 4;
-				}          
 				serverURI = command->command.details.conn.serverURIs[command->command.details.conn.currentURI];
 					
 				if (strncmp(URI_TCP, serverURI, strlen(URI_TCP)) == 0)
@@ -995,10 +1000,15 @@ void MQTTAsync_processCommand()
 #endif
 			}
 
-			if (command->command.details.conn.MQTTVersion == 0)
-				command->command.details.conn.MQTTVersion = 4;
-			else if (command->command.details.conn.MQTTVersion == 4)
-				command->command.details.conn.MQTTVersion = 3;
+			if (command->client->c->MQTTVersion == MQTTVERSION_DEFAULT)
+			{
+				if (command->command.details.conn.MQTTVersion == 0)
+					command->command.details.conn.MQTTVersion = MQTTVERSION_3_1_1;
+				else if (command->command.details.conn.MQTTVersion == MQTTVERSION_3_1_1)
+					command->command.details.conn.MQTTVersion = MQTTVERSION_3_1;
+			}
+			else
+				command->command.details.conn.MQTTVersion = command->client->c->MQTTVersion;
 
 			Log(TRACE_MIN, -1, "Connecting to serverURI %s with MQTT version %d", serverURI, command->command.details.conn.MQTTVersion);
 #if defined(OPENSSL)
@@ -1121,7 +1131,7 @@ void MQTTAsync_processCommand()
 		else
 			MQTTAsync_disconnect_internal(command->client, 0);
 			
-		if (command->command.type == CONNECT && MQTTAsync_checkConn(&command->command))
+		if (command->command.type == CONNECT && MQTTAsync_checkConn(&command->command, command->client))
 		{
 			Log(TRACE_MIN, -1, "Connect failed, more to try");
 			/* put the connect command back to the head of the command queue, using the next serverURI */
@@ -1175,7 +1185,7 @@ void MQTTAsync_checkTimeouts()
 		/* check connect timeout */
 		if (m->c->connect_state != 0 && MQTTAsync_elapsed(m->connect.start_time) > (m->connect.details.conn.timeout * 1000))
 		{
-			if (MQTTAsync_checkConn(&m->connect))
+			if (MQTTAsync_checkConn(&m->connect, m))
 			{
 				MQTTAsync_queuedCommand* conn;
 				
@@ -1185,7 +1195,7 @@ void MQTTAsync_checkTimeouts()
 				memset(conn, '\0', sizeof(MQTTAsync_queuedCommand));
 				conn->client = m;
 				conn->command = m->connect;
-				Log(TRACE_MIN, -1, "Connect failed, more to try");
+				Log(TRACE_MIN, -1, "Connect failed with timeout, more to try");
 				MQTTAsync_addCommand(conn, sizeof(m->connect));
 			}
 			else
@@ -1508,7 +1518,7 @@ thread_return_type WINAPI MQTTAsync_receiveThread(void* n)
 					}
 					else
 					{
-						if (MQTTAsync_checkConn(&m->connect))
+						if (MQTTAsync_checkConn(&m->connect, m))
 						{
 							MQTTAsync_queuedCommand* conn;
 							
@@ -2015,7 +2025,8 @@ int MQTTAsync_connect(MQTTAsync handle, MQTTAsync_connectOptions* options)
 	}
 
 	if (strncmp(options->struct_id, "MQTC", 4) != 0 || 
-		(options->struct_version != 0 && options->struct_version != 1 && options->struct_version != 2))
+		(options->struct_version != 0 && options->struct_version != 1 && options->struct_version != 2 && 
+         options->struct_version != 3))
 	{
 		rc = MQTTASYNC_BAD_STRUCTURE;
 		goto exit;
@@ -2071,6 +2082,10 @@ int MQTTAsync_connect(MQTTAsync handle, MQTTAsync_connectOptions* options)
 	m->c->keepAliveInterval = options->keepAliveInterval;
 	m->c->cleansession = options->cleansession;
 	m->c->maxInflightMessages = options->maxInflight;
+	if (options->struct_version == 3)
+		m->c->MQTTVersion = options->MQTTVersion;
+	else
+		m->c->MQTTVersion = 0;
 
 	if (m->c->will)
 	{
@@ -2572,7 +2587,7 @@ int MQTTAsync_connecting(MQTTAsyncs* m)
 exit:
 	if ((rc != 0 && rc != TCPSOCKET_INTERRUPTED && m->c->connect_state != 2) || (rc == SSL_FATAL))
 	{
-		if (MQTTAsync_checkConn(&m->connect))
+		if (MQTTAsync_checkConn(&m->connect, m))
 		{
 			MQTTAsync_queuedCommand* conn;
 				
@@ -2650,7 +2665,7 @@ MQTTPacket* MQTTAsync_cycle(int* sock, unsigned long timeout, int* rc)
 			if ((m->c->connect_state == 3) && (*rc == SOCKET_ERROR))
 			{
 				Log(TRACE_MINIMUM, -1, "CONNECT sent but MQTTPacket_Factory has returned SOCKET_ERROR");
-				if (MQTTAsync_checkConn(&m->connect))
+				if (MQTTAsync_checkConn(&m->connect, m))
 				{
 					MQTTAsync_queuedCommand* conn;
 				
diff --git a/src/MQTTAsync.h b/src/MQTTAsync.h
index 4df136ac..cab3caf5 100644
--- a/src/MQTTAsync.h
+++ b/src/MQTTAsync.h
@@ -14,6 +14,7 @@
  *    Ian Craggs - initial API and implementation 
  *    Ian Craggs, Allan Stockdill-Mander - SSL connections
  *    Ian Craggs - multiple server connection support
+ *    Ian Craggs - MQTT 3.1.1 support
  *******************************************************************************/
 
 /********************************************************************/
@@ -145,6 +146,19 @@
  */
 #define MQTTASYNC_NO_MORE_MSGIDS -10
 
+/**
+ * Default MQTT version to connect with.  Use 3.1.1 then fall back to 3.1
+ */
+#define MQTTVERSION_DEFAULT 0
+/**
+ * MQTT version to connect with: 3.1
+ */
+#define MQTTVERSION_3_1 3
+/**
+ * MQTT version to connect with: 3.1.1
+ */
+#define MQTTVERSION_3_1_1 4
+
 /**
  * A handle representing an MQTT client. A valid client handle is available
  * following a successful call to MQTTAsync_create().
@@ -549,9 +563,10 @@ typedef struct
 {
 	/** The eyecatcher for this structure.  must be MQTC. */
 	char struct_id[4];
-	/** The version number of this structure.  Must be 0, 1 or 2.  
+	/** The version number of this structure.  Must be 0, 1, 2 or 3.  
 	  * 0 signifies no SSL options and no serverURIs
 	  * 1 signifies no serverURIs 
+      * 2 signifies no MQTTVersion
 	  */
 	int struct_version;
 	/** The "keep alive" interval, measured in seconds, defines the maximum time
@@ -653,10 +668,17 @@ typedef struct
       * <i>tcp://localhost:1883</i>.
       */    
 	char** serverURIs;
+	/**
+      * Sets the version of MQTT to be used on the connect.
+      * MQTTVERSION_DEFAULT (0) = default: start with 3.1.1, and if that fails, fall back to 3.1
+      * MQTTVERSION_3_1 (3) = only try version 3.1
+      * MQTTVERSION_3_1_1 (4) = only try version 3.1.1
+	  */
+	int MQTTVersion;
 } MQTTAsync_connectOptions;
 
 
-#define MQTTAsync_connectOptions_initializer { {'M', 'Q', 'T', 'C'}, 2, 60, 1, 10, NULL, NULL, NULL, 30, 20, NULL, NULL, 0, NULL}
+#define MQTTAsync_connectOptions_initializer { {'M', 'Q', 'T', 'C'}, 3, 60, 1, 10, NULL, NULL, NULL, 30, 20, NULL, NULL, 0, NULL, 0}
 
 /**
   * This function attempts to connect a previously-created client (see
diff --git a/src/MQTTClient.c b/src/MQTTClient.c
index 7bf671b8..bb0fea99 100644
--- a/src/MQTTClient.c
+++ b/src/MQTTClient.c
@@ -748,7 +748,7 @@ int MQTTClient_connectURIVersion(MQTTClient handle, MQTTClient_connectOptions* o
 	MQTTClients* m = handle;
 	int rc = SOCKET_ERROR;
 
-  FUNC_ENTRY;
+	FUNC_ENTRY;
 	if (m->ma && !running)
 	{
 		Thread_start(MQTTClient_run, handle);
@@ -914,6 +914,7 @@ int MQTTClient_connectURI(MQTTClient handle, MQTTClient_connectOptions* options,
 	START_TIME_TYPE start;
 	long millisecsTimeout = 30000L;
 	int rc = SOCKET_ERROR;
+	int MQTTVersion = 0;
 
 	FUNC_ENTRY;
 	millisecsTimeout = options->connectTimeout * 1000;
@@ -996,8 +997,18 @@ int MQTTClient_connectURI(MQTTClient handle, MQTTClient_connectOptions* options,
 	m->c->password = options->password;
 	m->c->retryInterval = options->retryInterval;
 
-	if ((rc = MQTTClient_connectURIVersion(handle, options, serverURI, 4	, start, millisecsTimeout)) != MQTTCLIENT_SUCCESS)
-		rc = MQTTClient_connectURIVersion(handle, options, serverURI, 3, start, millisecsTimeout);
+	if (options->struct_version == 3)
+		MQTTVersion = options->MQTTVersion;
+	else
+		MQTTVersion = MQTTVERSION_DEFAULT;
+
+	if (MQTTVersion == MQTTVERSION_DEFAULT)
+	{
+		if ((rc = MQTTClient_connectURIVersion(handle, options, serverURI, 4	, start, millisecsTimeout)) != MQTTCLIENT_SUCCESS)
+			rc = MQTTClient_connectURIVersion(handle, options, serverURI, 3, start, millisecsTimeout);
+	}
+	else
+		rc = MQTTClient_connectURIVersion(handle, options, serverURI, MQTTVersion, start, millisecsTimeout);
 
 	FUNC_EXIT_RC(rc);
 	return rc;
diff --git a/src/MQTTClient.h b/src/MQTTClient.h
index ec352196..bf81372b 100644
--- a/src/MQTTClient.h
+++ b/src/MQTTClient.h
@@ -14,6 +14,7 @@
  *    Ian Craggs - initial API and implementation and/or initial documentation
  *    Ian Craggs, Allan Stockdill-Mander - SSL updates
  *    Ian Craggs - multiple server connection support
+ *    Ian Craggs - MQTT 3.1.1 support
  *******************************************************************************/
 
 /**
@@ -160,6 +161,19 @@
  */
 #define MQTTCLIENT_BAD_QOS -9
 
+/**
+ * Default MQTT version to connect with.  Use 3.1.1 then fall back to 3.1
+ */
+#define MQTTVERSION_DEFAULT 0
+/**
+ * MQTT version to connect with: 3.1
+ */
+#define MQTTVERSION_3_1 3
+/**
+ * MQTT version to connect with: 3.1.1
+ */
+#define MQTTVERSION_3_1_1 4
+
 /**
  * A handle representing an MQTT client. A valid client handle is available
  * following a successful call to MQTTClient_create().
@@ -490,9 +504,10 @@ typedef struct
 {
 	/** The eyecatcher for this structure.  must be MQTC. */
 	char struct_id[4];
-	/** The version number of this structure.  Must be 0, 1 or 2.  
+	/** The version number of this structure.  Must be 0, 1, 2 or 3.  
 	  * 0 signifies no SSL options and no serverURIs
 	  * 1 signifies no serverURIs 
+      * 2 signifies no MQTTVersion
 	  */
 	int struct_version;
 	/** The "keep alive" interval, measured in seconds, defines the maximum time
@@ -583,9 +598,16 @@ typedef struct
    * is used.
    */    
 	char** serverURIs;
+	/**
+      * Sets the version of MQTT to be used on the connect.
+      * MQTTVERSION_DEFAULT (0) = default: start with 3.1.1, and if that fails, fall back to 3.1
+      * MQTTVERSION_3_1 (3) = only try version 3.1
+      * MQTTVERSION_3_1_1 (4) = only try version 3.1.1
+	  */
+	int MQTTVersion;
 } MQTTClient_connectOptions;
 
-#define MQTTClient_connectOptions_initializer { {'M', 'Q', 'T', 'C'}, 2, 60, 1, 1, NULL, NULL, NULL, 30, 20, NULL, 0, NULL }
+#define MQTTClient_connectOptions_initializer { {'M', 'Q', 'T', 'C'}, 2, 60, 1, 1, NULL, NULL, NULL, 30, 20, NULL, 0, NULL, 0}
 
 /**
   * MQTTClient_libraryInfo is used to store details relating to the currently used
diff --git a/src/MQTTProtocol.h b/src/MQTTProtocol.h
index a597a65e..74781030 100644
--- a/src/MQTTProtocol.h
+++ b/src/MQTTProtocol.h
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2009, 2013 IBM Corp.
+ * Copyright (c) 2009, 2014 IBM Corp.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
@@ -12,6 +12,7 @@
  *
  * Contributors:
  *    Ian Craggs - initial API and implementation and/or initial documentation
+ *    Ian Craggs - MQTT 3.1.1 updates
  *******************************************************************************/
 
 #if !defined(MQTTPROTOCOL_H)
@@ -22,7 +23,7 @@
 #include "Clients.h"
 
 #define MAX_MSG_ID 65535
-#define MAX_CLIENTID_LEN 23
+#define MAX_CLIENTID_LEN 65535
 
 typedef struct
 {
diff --git a/src/MQTTProtocolClient.h b/src/MQTTProtocolClient.h
index b1406d52..116d1b22 100644
--- a/src/MQTTProtocolClient.h
+++ b/src/MQTTProtocolClient.h
@@ -13,6 +13,7 @@
  * Contributors:
  *    Ian Craggs - initial API and implementation and/or initial documentation
  *    Ian Craggs, Allan Stockdill-Mander - SSL updates
+ *    Ian Craggs - MQTT 3.1.1 updates
  *******************************************************************************/
 
 #if !defined(MQTTPROTOCOLCLIENT_H)
@@ -25,7 +26,7 @@
 #include "Messages.h"
 
 #define MAX_MSG_ID 65535
-#define MAX_CLIENTID_LEN 23
+#define MAX_CLIENTID_LEN 65535
 
 int MQTTProtocol_assignMsgId(Clients* client);
 int MQTTProtocol_startPublish(Clients* pubclient, Publish* publish, int qos, int retained, Messages** m);
diff --git a/test/test4.c b/test/test4.c
index 9e29a94a..df7af4ee 100644
--- a/test/test4.c
+++ b/test/test4.c
@@ -61,14 +61,18 @@ struct Options
 {
 	char* connection;         /**< connection to system under test. */
 	int verbose;
-  int test_no;
+	int test_no;
 	int size;									/**< size of big message */
+	int MQTTVersion;
+	int iterations;
 } options =
 {
 	"m2m.eclipse.org:1883",
 	0,
 	-1,
 	10000,
+	MQTTVERSION_DEFAULT,
+	1,
 };
 
 void getopts(int argc, char** argv)
@@ -98,6 +102,23 @@ void getopts(int argc, char** argv)
 			else
 				usage();
 		}
+		else if (strcmp(argv[count], "--MQTTversion") == 0)
+		{
+			if (++count < argc)
+			{
+				options.MQTTVersion = atoi(argv[count]);
+				printf("setting MQTT version to %d\n", options.MQTTVersion);
+			}
+			else
+				usage();
+		}
+		else if (strcmp(argv[count], "--iterations") == 0)
+		{
+			if (++count < argc)
+				options.iterations = atoi(argv[count]);
+			else
+				usage();
+		}
 		else if (strcmp(argv[count], "--verbose") == 0)
 			options.verbose = 1;
 		count++;
@@ -370,6 +391,7 @@ int test1(struct Options options)
 	opts.cleansession = 1;
 	opts.username = "testuser";
 	opts.password = "testpassword";
+	opts.MQTTVersion = options.MQTTVersion; 
 
 	opts.will = &wopts;
 	opts.will->message = "will message";
@@ -462,6 +484,7 @@ int test2(struct Options options)
 	opts.cleansession = 1;
 	opts.username = "testuser";
 	opts.password = "testpassword";
+	opts.MQTTVersion = options.MQTTVersion;
 
 	opts.will = &wopts;
 	opts.will->message = "will message";
@@ -674,6 +697,7 @@ int test3(struct Options options)
 		opts.cleansession = 1;
 		opts.username = "testuser";
 		opts.password = "testpassword";
+		opts.MQTTVersion = options.MQTTVersion;
 
 		opts.will = &wopts;
 		opts.will->message = "will message";
@@ -861,6 +885,7 @@ int test4(struct Options options)
 	opts.cleansession = 1;
 	opts.username = "testuser";
 	opts.password = "testpassword";
+	opts.MQTTVersion = options.MQTTVersion;
 
 	opts.will = &wopts;
 	opts.will->message = "will message";
@@ -1051,6 +1076,7 @@ int test6(struct Options options)
 	opts.onSuccess = test6_onConnect;
 	opts.onFailure = test6_onConnectFailure;
 	opts.context = &cinfo;
+	opts.MQTTVersion = options.MQTTVersion;
 
 	MyLog(LOGA_DEBUG, "Connecting");
 	rc = MQTTAsync_connect(cinfo.c, &opts);
diff --git a/test/test5.c b/test/test5.c
index 92f45c07..d5d14177 100644
--- a/test/test5.c
+++ b/test/test5.c
@@ -438,7 +438,6 @@ void asyncTestOnDisconnect(void* context, MQTTAsync_successData* response)
 
 	AsyncTestClient* tc = (AsyncTestClient*) context;
 	MyLog(LOGA_DEBUG, "In asyncTestOnDisconnect callback, %s", tc->clientid);
-	printf("Successful disconnection\n");
 	//rc = Thread_lock_mutex(client_mutex);
 	tc->testFinished = 1;
 	//rc = Thread_unlock_mutex(client_mutex);