Index: firmware/App/Services/SystemCommMessages.h
===================================================================
diff -u -rea731c287a4e43901956aaa9a0009a5ee8f4671f -rc9eae083ca9c06f843ce7ebd7ef93ff47a986011
--- firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision ea731c287a4e43901956aaa9a0009a5ee8f4671f)
+++ firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision c9eae083ca9c06f843ce7ebd7ef93ff47a986011)
@@ -64,32 +64,23 @@
 #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
 {
-    BOOL accepted;              ///< Accepted/Rejected
-    U32 rejectionReason;        ///< Rejection reason if not accepted.
-} UI_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
 {
-    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;
+    BOOL accepted;              ///< Accepted/Rejected
+    U32 rejectionReason;        ///< Rejection reason if not accepted.
+} UI_RESPONSE_PAYLOAD_T;
 
 typedef struct
 {
@@ -130,6 +121,15 @@
 
 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)