Index: firmware/App/Services/MsgQueues.h
===================================================================
diff -u -reff7b1575f008f81b29ef906f6346fac6012d3ab -re5bb82cad756fbb10f04d576dffd499df78f6b35
--- firmware/App/Services/MsgQueues.h	(.../MsgQueues.h)	(revision eff7b1575f008f81b29ef906f6346fac6012d3ab)
+++ firmware/App/Services/MsgQueues.h	(.../MsgQueues.h)	(revision e5bb82cad756fbb10f04d576dffd499df78f6b35)
@@ -1,6 +1,6 @@
 /**************************************************************************
  *
- *  Copyright (c) 2019-2019 Diality Inc. - All Rights Reserved.
+ *  Copyright (c) 2019-2020 Diality Inc. - All Rights Reserved.
  *
  *  THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
  *  WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
@@ -17,11 +17,11 @@
 #ifndef __MSG_QUEUES_H__
 #define __MSG_QUEUES_H__
 
-#include "Common.h"
+#include "../HDCommon.h"
 
 // ********** public definitions **********
 
-#define MAX_MSG_CARGO_SIZE          100         // bytes
+#define MAX_MSG_PAYLOAD_SIZE          100         // bytes
 
 typedef enum Msg_Queues
 {
@@ -32,14 +32,17 @@
 #pragma pack(push,1)
 typedef struct
 {
+#ifndef ACK_NOT_IMPLEMENTED
+    S16 seqNo;                                  // sequence # (and ACK required bit) of message
+#endif
     U16 msgID;                                  // ID of message
-    U08 cargoLen;                               // length of cargo in bytes
+    U08 payloadLen;                             // length of payload in bytes
 } MESSAGE_HEADER_T;
 
 typedef struct
 {
     MESSAGE_HEADER_T hdr;                       // message header
-    U08              cargo[MAX_MSG_CARGO_SIZE]; // message cargo
+    U08              payload[ MAX_MSG_PAYLOAD_SIZE ]; // message payload
 } MESSAGE_T;
 
 typedef struct