Index: MessagePayloads.h
===================================================================
diff -u -r281e9fc146b02976566d167d5e08a8a9af291c99 -r8338940cee3dc237a0304d0975028865f25971db
--- MessagePayloads.h	(.../MessagePayloads.h)	(revision 281e9fc146b02976566d167d5e08a8a9af291c99)
+++ MessagePayloads.h	(.../MessagePayloads.h)	(revision 8338940cee3dc237a0304d0975028865f25971db)
@@ -61,6 +61,12 @@
     U32  bicarbonate;                                   ///< Set bicarbonate being used to make dialysate.
 } PRE_GEN_DIALYSATE_REQ_PAYLOAD_T;
 
+/// Payload record structure for requesting DD heat disinfect.
+typedef struct
+{
+    BOOL start;                                         ///< Flag indicating whether to start heat disinfect (TRUE) or stop (FALSE).
+} HEAT_DISINFECT_REQ_PAYLOAD_T;
+
 /// Payload record structure for requesting RO water.
 typedef struct
 {
@@ -103,8 +109,11 @@
 typedef struct
 {
     U32 heatDisinfectExecState;            ///< Heat disinfect execution state
+    U32 heatDisinfectSubState;             ///< Depressurize sub-state, or 0xFF if not applicable
     U32 ddRecircDwellTimeMS;               ///< Current DD recirculation dwell time
     U32 wcidRecircDwellTimeMS;             ///< Current WCID recirculation dwell time
+    U32 ddDwellAtTarget;                   ///< TRUE while D78 is above DD dwell temperature
+    U32 wcidDwellAtTarget;                 ///< TRUE while D4 is above WCID dwell temperature
 } HEAT_DISINFECT_STATE_DATA_T;
 
 #pragma pack(pop)