Index: firmware/App/Services/SystemCommMessages.h
===================================================================
diff -u -r876a1cdab00a28265349cec424f77709a101db5c -r57dd046b04afac3364f6adc7d47252d73cacab4d
--- firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision 876a1cdab00a28265349cec424f77709a101db5c)
+++ firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision 57dd046b04afac3364f6adc7d47252d73cacab4d)
@@ -8,7 +8,7 @@
 * @file    SystemCommMessages.h
 *
 * @author  (last)      Michael Garthwaite
-* @date    (last)      07-Feb-2023
+* @date    (last)      08-Mar-2023
 *
 * @author  (original)  Dara Navaei
 * @date    (original)  05-Nov-2019
@@ -63,6 +63,80 @@
 
 #define ACK_REQUIRED                    TRUE                ///< Macro for functions that want to know if an outgoing message requires acknowledgement from receiver.
 #define ACK_NOT_REQUIRED                FALSE               ///< Macro for functions that want to know if an outgoing message requires acknowledgement from receiver.
+
+#pragma pack(push, 1)
+typedef struct
+{
+    U08 acknowledgement;         ///< Acknowledgement Byte
+} ACK_RESPONSE_PAYLOAD_T;
+
+typedef struct
+{
+    U08 userRequest;            ///< request to confirm, cancel, or reject off button request
+} UI_OFF_BUTTON_RESPONSE_PAYLOAD_T;
+#pragma pack(pop)
+
+typedef struct
+{
+    BOOL accepted;              ///< Accepted/Rejected
+    U32 rejectionReason;        ///< Rejection reason if not accepted.
+} UI_RESPONSE_PAYLOAD_T;
+
+typedef struct
+{
+    BOOL accepted;              ///< Accepted/Rejected
+    U32 rejectionReason;        ///< Rejection reason if not accepted.
+    F32 ufVolume;               ///< UF Volume in mL.
+    U32 durationInMinutes;      ///< new Treatment duration in minutes.
+    S32 timeDiff;               ///< Treatment duration difference.
+    F32 ufRate;                 ///< new UF rate in mL/min.
+    F32 rateDiff;               ///< difference between new and old UF rates.
+    F32 oldUFRate;              ///< Previous UF Rate in mL/min.
+} UF_SETTINGS_CHANGE_RESPONSE_PAYLOAD_T;
+
+typedef struct
+{
+    BOOL accepted;              ///< Accepted/Rejected
+    U32 rejectionReason;        ///< Rejection reason if not accepted.
+    F32 volume;                 ///< UF Volume in mL.
+    U32 duration;               ///< Treatment duration in minutes
+    F32 ufRate;                 ///< UF rate in mL.
+} UF_SETTINGS_CONFIRMATION_RESPONSE_PAYLOAD_T;
+
+typedef struct
+{
+    BOOL accepted;              ///< Accepted/Rejected
+    U32 rejectionReason;        ///< Rejection reason if not accepted.
+    U32 duration;               ///< Treatment duration in minutes
+    F32 volume;                 ///< UF Volume in mL.
+} TREATMENT_TIME_CHANGE_RESPONSE_PAYLOAD_T;
+
+typedef struct
+{
+    BOOL accepted;              ///< Accepted/Rejected
+    U32 rejectionReason;        ///< Rejection reason if not accepted.
+    U32 bloodRate;              ///< new blood flow rate
+    U32 dialRate;               ///< new dialysate flow rate
+} BLOOD_DIAL_RATE_CHANGE_RESPONSE_PAYLOAD_T;
+
+typedef struct
+{
+    U32 event;                  ///< Event ID
+    U32 dataType1;              ///< Data type for data field 1
+    EVENT_DATAS_T data1;        ///< data field 1
+    U32 dataType2;              ///< Data type for data field 2
+    EVENT_DATAS_T data2;        ///< Data field 2
+} EVENT_PAYLOAD_T;
+
+typedef struct
+{
+    U32 minTreatmentTime;       ///< Minimum treatment duration (in minutes)
+    U32 maxTreatmentTime;       ///< Maximum treatment duration (in minutes)
+    F32 minUFVolume;            ///< Minimum ultrafiltration volume (in mL)
+    F32 maxUFVolume;            ///< Maximum ultrafiltration volume (in mL)
+    U32 minDialRate;            ///< Minimum dialysate flow rate (in mL/min)
+    U32 maxDialRate;            ///< Maximum dialysate flow rate (in mL/min)
+} TREATMENT_PARAM_BROADCAST_PAYLOAD_T;
 
 // ********** public function prototypes **********
 
@@ -347,7 +421,7 @@
 void handleUIActiveAlarmsListRequest( MESSAGE_T *message );
 
 // MSG_ID_HD_ACTIVE_ALARMS_LIST_REQUEST_RESPONSE
-BOOL sendActiveAlarmsList( BOOL accepted, U32 reason, U32 *alarmList, U32 size );
+BOOL sendActiveAlarmsList( ACTIVE_ALARM_LIST_RESPONSE_PAYLOAD_T alarmListPayload );
 
 // MSG_ID_HD_TREATMENT_LOG_ALARM_EVENT
 BOOL sendTreatmentLogAlarmEventData( ALARM_ID_T alarmID, ALARM_DATA_T almData1, ALARM_DATA_T almData2 );