diff --git a/Adafruit_MQTT.cpp b/Adafruit_MQTT.cpp
index b5836f4..7a5616e 100644
--- a/Adafruit_MQTT.cpp
+++ b/Adafruit_MQTT.cpp
@@ -472,11 +472,16 @@ void Adafruit_MQTT::processPackets(int16_t timeout) {
 	//Serial.print("*** calling double callback with : "); Serial.println(data);
 	sub->callback_double(data);
       }
-      else if (sub->callback_buffer != NULL) {
+      else if (sub->callback_buffer != null) {
 	// huh lets do the callback in buffer mode
-	//Serial.print("*** calling buffer callback with : "); Serial.println(data);
+	//serial.print("*** calling buffer callback with : "); serial.println(data);
 	sub->callback_buffer((char *)sub->lastread, sub->datalen);
       }
+      else if (sub->callback_io != null) {
+        // huh lets do the callback in io mode
+        //serial.print("*** calling io instance callback with : "); serial.println(data);
+        sub->callback_io((char *)sub->lastread, sub->datalen);
+      }
     }
 
     // keep track over elapsed time
@@ -861,6 +866,7 @@ Adafruit_MQTT_Subscribe::Adafruit_MQTT_Subscribe(Adafruit_MQTT *mqttserver,
   callback_uint32t = 0;
   callback_buffer = 0;
   callback_double = 0;
+  callback_io = 0;
 }
 
 Adafruit_MQTT_Subscribe::Adafruit_MQTT_Subscribe(Adafruit_MQTT *mqttserver,
@@ -871,7 +877,7 @@ Adafruit_MQTT_Subscribe::Adafruit_MQTT_Subscribe(Adafruit_MQTT *mqttserver,
   datalen = 0;
   callback_uint32t = 0;
   callback_buffer = 0;
-  callback_double = 0;
+  callback_io = 0;
 }
 
 void Adafruit_MQTT_Subscribe::setCallback(SubscribeCallbackUInt32Type cb) {
@@ -886,8 +892,13 @@ void Adafruit_MQTT_Subscribe::setCallback(SubscribeCallbackBufferType cb) {
   callback_buffer = cb;
 }
 
+void Adafruit_MQTT_Subscribe::setCallback(SubscribeCallbackIOType cb) {
+  callback_io = cb;
+}
+
 void Adafruit_MQTT_Subscribe::removeCallback(void) {
   callback_uint32t = 0;
   callback_buffer = 0;
   callback_double = 0;
+  callback_io = 0;
 }
diff --git a/Adafruit_MQTT.h b/Adafruit_MQTT.h
index dbdecb0..169613b 100644
--- a/Adafruit_MQTT.h
+++ b/Adafruit_MQTT.h
@@ -108,12 +108,16 @@
 // eg max-subscription-payload-size
 #define SUBSCRIPTIONDATALEN 20
 
+class AdafruitIO_Feed;  // forward decl
+
 //Function pointer that returns an int
 typedef void (*SubscribeCallbackUInt32Type)(uint32_t);
 // returns a double
 typedef void (*SubscribeCallbackDoubleType)(double);
 // returns a chunk of raw data
 typedef void (*SubscribeCallbackBufferType)(char *str, uint16_t len);
+// returns an io data wrapper instance
+typedef void (AdafruitIO_Feed::*SubscribeCallbackIOType)(char *str, uint16_t len);
 
 extern void printBuffer(uint8_t *buffer, uint16_t len);
 
@@ -284,6 +288,7 @@ class Adafruit_MQTT_Subscribe {
   void setCallback(SubscribeCallbackUInt32Type callb);
   void setCallback(SubscribeCallbackDoubleType callb);
   void setCallback(SubscribeCallbackBufferType callb);
+  void setCallback(SubscribeCallbackIOType callb);
   void removeCallback(void);
 
   const char *topic;
@@ -297,6 +302,7 @@ class Adafruit_MQTT_Subscribe {
   SubscribeCallbackUInt32Type callback_uint32t;
   SubscribeCallbackDoubleType callback_double;
   SubscribeCallbackBufferType callback_buffer;
+  SubscribeCallbackIOType     callback_io;
 
  private:
   Adafruit_MQTT *mqtt;