From c753ecaebe6dd9160bed6b8fcd8645824b3079dd Mon Sep 17 00:00:00 2001
From: Nick O'Leary <nick.oleary@gmail.com>
Date: Wed, 26 Aug 2015 23:07:22 +0100
Subject: [PATCH] Add MQTT 3.1.1 support

---
 PubSubClient/PubSubClient.cpp | 11 +++++++++--
 PubSubClient/PubSubClient.h   |  7 ++++++-
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/PubSubClient/PubSubClient.cpp b/PubSubClient/PubSubClient.cpp
index 75c4272..c4da0c5 100755
--- a/PubSubClient/PubSubClient.cpp
+++ b/PubSubClient/PubSubClient.cpp
@@ -66,11 +66,18 @@ boolean PubSubClient::connect(char *id, char *user, char *pass, char* willTopic,
 
       if (result) {
          nextMsgId = 1;
-         uint8_t d[9] = {0x00,0x06,'M','Q','I','s','d','p',MQTTPROTOCOLVERSION};
          // Leave room in the buffer for header and variable length field
          uint16_t length = 5;
          unsigned int j;
-         for (j = 0;j<9;j++) {
+
+#if MQTT_VERSION == MQTT_VERSION_3_1
+         uint8_t d[9] = {0x00,0x06,'M','Q','I','s','d','p', MQTT_VERSION};
+#define MQTT_HEADER_VERSION_LENGTH 9
+#elif MQTT_VERSION == MQTT_VERSION_3_1_1
+         uint8_t d[7] = {0x00,0x04,'M','Q','T','T',MQTT_VERSION};
+#define MQTT_HEADER_VERSION_LENGTH 7
+#endif
+         for (j = 0;j<MQTT_HEADER_VERSION_LENGTH;j++) {
             buffer[length++] = d[j];
          }
 
diff --git a/PubSubClient/PubSubClient.h b/PubSubClient/PubSubClient.h
index a896c9d..3e5dbdd 100755
--- a/PubSubClient/PubSubClient.h
+++ b/PubSubClient/PubSubClient.h
@@ -11,13 +11,18 @@
 #include "Client.h"
 #include "Stream.h"
 
+#define MQTT_VERSION_3_1      3
+#define MQTT_VERSION_3_1_1    4
+
+// MQTT_VERSION
+#define MQTT_VERSION MQTT_VERSION_3_1_1
+
 // MQTT_MAX_PACKET_SIZE : Maximum packet size
 #define MQTT_MAX_PACKET_SIZE 128
 
 // MQTT_KEEPALIVE : keepAlive interval in Seconds
 #define MQTT_KEEPALIVE 15
 
-#define MQTTPROTOCOLVERSION 3
 #define MQTTCONNECT     1 << 4  // Client request to connect to Server
 #define MQTTCONNACK     2 << 4  // Connect Acknowledgment
 #define MQTTPUBLISH     3 << 4  // Publish message