diff --git a/Adafruit_MQTT.cpp b/Adafruit_MQTT.cpp
index 5558a65..5a9c5f2 100644
--- a/Adafruit_MQTT.cpp
+++ b/Adafruit_MQTT.cpp
@@ -119,13 +119,13 @@ int8_t Adafruit_MQTT::connect() {
   // Connect to the server.
   if (!connectServer())
     return -1;
-  
+
   // Construct and send connect packet.
   uint8_t len = connectPacket(buffer);
   if (!sendPacket(buffer, len))
     return -1;
 
-  // Read connect response packet and verify it  
+  // Read connect response packet and verify it
   len = readPacket(buffer, 4, CONNECT_TIMEOUT_MS);
   if (len != 4)
     return -1;
@@ -143,7 +143,7 @@ int8_t Adafruit_MQTT::connect() {
     uint8_t len = subscribePacket(buffer, subscriptions[i]->topic, subscriptions[i]->qos);
     if (!sendPacket(buffer, len))
       return -1;
-    
+
     // Get SUBACK
     len = readPacket(buffer, 5, CONNECT_TIMEOUT_MS);
     DEBUG_PRINT(F("SUBACK:\t"));
diff --git a/Adafruit_MQTT.h b/Adafruit_MQTT.h
index e18110e..f093254 100644
--- a/Adafruit_MQTT.h
+++ b/Adafruit_MQTT.h
@@ -29,7 +29,7 @@
 #endif
 
 // Uncomment/comment to turn on/off debug output messages.
-//#define MQTT_DEBUG
+#define MQTT_DEBUG
 
 // Set where debug messages will be printed.
 #define DEBUG_PRINTER Serial
@@ -45,7 +45,9 @@
   #define DEBUG_PRINTBUFFER(buffer, len) {}
 #endif
 
-#define MQTT_PROTOCOL_LEVEL 3
+#ifndef MQTT_PROTOCOL_LEVEL
+  #define MQTT_PROTOCOL_LEVEL 4
+#endif
 
 #define MQTT_CTRL_CONNECT 0x01
 #define MQTT_CTRL_CONNECTACK 0x02