Index: firmware/App/Modes/ConsumableSelfTest.c
===================================================================
diff -u -r0a4dcd288d4347b85baaa0b07da568b6add5eac7 -r82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215
--- firmware/App/Modes/ConsumableSelfTest.c	(.../ConsumableSelfTest.c)	(revision 0a4dcd288d4347b85baaa0b07da568b6add5eac7)
+++ firmware/App/Modes/ConsumableSelfTest.c	(.../ConsumableSelfTest.c)	(revision 82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215)
@@ -91,6 +91,8 @@
  *************************************************************************/
 void execConsumableSelfTest( void )
 {
+    CONSUMABLE_SELF_TESTS_STATE_T priorSubState = currentConsumableSelfTestState;
+
     switch( currentConsumableSelfTestState )
     {
         case CONSUMABLE_SELF_TESTS_INSTALL_STATE:
@@ -157,6 +159,10 @@
             break;
     }
 
+    if ( priorSubState != currentConsumableSelfTestState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentConsumableSelfTestState );
+    }
     // Handle triggered alarm with stop property
     handleConsumableSelfTestStopRequest();
 }
Index: firmware/App/Modes/Dialysis.c
===================================================================
diff -u -r0a4dcd288d4347b85baaa0b07da568b6add5eac7 -r82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215
--- firmware/App/Modes/Dialysis.c	(.../Dialysis.c)	(revision 0a4dcd288d4347b85baaa0b07da568b6add5eac7)
+++ firmware/App/Modes/Dialysis.c	(.../Dialysis.c)	(revision 82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215)
@@ -623,6 +623,8 @@
  *************************************************************************/
 void execDialysis( void )
 {
+    DIALYSIS_STATE_T priorSubState = currentDialysisState;
+
     // Check ultrafiltration max rate and accuracy during dialysis (even when ultrafiltration is paused).
     checkUFAccuracyAndVolume();
 
@@ -646,6 +648,10 @@
             break;
     }
 
+    if ( priorSubState != currentDialysisState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentDialysisState );
+    }
     // Publish saline bolus data at set interval (whether we are delivering one or not)
     publishSalineBolusData();
 }
@@ -661,6 +667,7 @@
 static DIALYSIS_STATE_T handleDialysisUltrafiltrationState( void )
 {
     DIALYSIS_STATE_T result = DIALYSIS_UF_STATE;
+    UF_STATE_T priorSubState = currentUFState;
     U32 preStop = getTreatmentParameterU32( TREATMENT_PARAM_HEPARIN_PRE_STOP_TIME );
     F32 minRem  = (F32)getTreatmentTimeRemainingSecs() / (F32)SEC_PER_MIN;
 
@@ -697,6 +704,11 @@
             break;
     }
 
+    if ( priorSubState != currentUFState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentUFState );
+    }
+
     return result;
 }
 
@@ -712,6 +724,8 @@
 {
     DIALYSIS_STATE_T result = DIALYSIS_SALINE_BOLUS_STATE;
 
+    SALINE_BOLUS_STATE_T priorSubState = currentSalineBolusState;
+
     switch ( currentSalineBolusState )
     {
         case SALINE_BOLUS_STATE_IDLE:
@@ -736,6 +750,11 @@
             break;
     }
 
+    if ( priorSubState != currentSalineBolusState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentSalineBolusState );
+    }
+
     return result;
 }
 
Index: firmware/App/Modes/ModePostTreat.c
===================================================================
diff -u -r775f8ad98cccfd06d712ab339d1d88e3e640803c -r82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215
--- firmware/App/Modes/ModePostTreat.c	(.../ModePostTreat.c)	(revision 775f8ad98cccfd06d712ab339d1d88e3e640803c)
+++ firmware/App/Modes/ModePostTreat.c	(.../ModePostTreat.c)	(revision 82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215)
@@ -171,6 +171,7 @@
 U32 execPostTreatmentMode( void )
 {
     BOOL stop = isStopButtonPressed();
+    HD_POST_TREATMENT_STATE_T priorSubState = currentPostTreatmentState;
 
     switch ( currentPostTreatmentState )
     {
@@ -195,6 +196,11 @@
             break;
     }
 
+    if ( priorSubState != currentPostTreatmentState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_MODE_CHANGE, priorSubState, currentPostTreatmentState );
+    }
+
     if ( ++postTreatmentPublishTimerCounter >= getU32OverrideValue( &postTreatmentModePublishInterval ) )
     {
         POST_TREATMENT_STATE_DATA_T data;
@@ -512,6 +518,8 @@
  *************************************************************************/
 static void execDrainReservoirs( void )
 {
+    DRAIN_STATE_T priorSubState = currentDrainReservoirState;
+
     switch ( currentDrainReservoirState )
     {
         case DRAIN_DG_DEPRIME_STATE:
@@ -538,6 +546,11 @@
             SET_ALARM_WITH_2_U32_DATA( ALARM_ID_HD_SOFTWARE_FAULT, SW_FAULT_ID_POST_TREATMENT_RESERVOIR_MGMT_INVALID_STATE, currentDrainReservoirState );
             break;
     }
+
+    if ( priorSubState != currentDrainReservoirState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentDrainReservoirState );
+    }
 }
 
 /*********************************************************************//**
Index: firmware/App/Modes/ModeTreatmentParams.c
===================================================================
diff -u -r0a4dcd288d4347b85baaa0b07da568b6add5eac7 -r82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215
--- firmware/App/Modes/ModeTreatmentParams.c	(.../ModeTreatmentParams.c)	(revision 0a4dcd288d4347b85baaa0b07da568b6add5eac7)
+++ firmware/App/Modes/ModeTreatmentParams.c	(.../ModeTreatmentParams.c)	(revision 82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215)
@@ -276,6 +276,7 @@
  *************************************************************************/
 U32 execTreatParamsMode( void )
 {
+    HD_TREATMENT_PARAMS_MODE_STATE_T priorSubState = currentTreatmentParamsState;
     BOOL stop = isStopButtonPressed();
 
     if ( TRUE == stop )
@@ -304,6 +305,11 @@
 
     }
 
+    if ( priorSubState != currentTreatmentParamsState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentTreatmentParamsState );
+    }
+
     return (U32)currentTreatmentParamsState;
 }
 
Index: firmware/App/Modes/PreTreatmentRecirc.c
===================================================================
diff -u -r0a4dcd288d4347b85baaa0b07da568b6add5eac7 -r82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215
--- firmware/App/Modes/PreTreatmentRecirc.c	(.../PreTreatmentRecirc.c)	(revision 0a4dcd288d4347b85baaa0b07da568b6add5eac7)
+++ firmware/App/Modes/PreTreatmentRecirc.c	(.../PreTreatmentRecirc.c)	(revision 82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215)
@@ -85,6 +85,8 @@
  *************************************************************************/
 void execPreTreatmentRecirc( void )
 {
+    HD_PRE_TREATMENT_RECIRC_STATE_T priorSubState = currentPreTreatmentRecircState;
+
     // execute pre-treatment recirculate state machine
     switch ( currentPreTreatmentRecircState )
     {
@@ -101,6 +103,10 @@
             break;
     }
 
+    if ( priorSubState != currentPreTreatmentRecircState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentPreTreatmentRecircState );
+    }
     // All flags should be handled by now, reset in case flags not handle in current state
     resetPreTreatmentRecircFlags();
 }
Index: firmware/App/Modes/Prime.c
===================================================================
diff -u -r0a4dcd288d4347b85baaa0b07da568b6add5eac7 -r82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215
--- firmware/App/Modes/Prime.c	(.../Prime.c)	(revision 0a4dcd288d4347b85baaa0b07da568b6add5eac7)
+++ firmware/App/Modes/Prime.c	(.../Prime.c)	(revision 82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215)
@@ -218,6 +218,7 @@
  *************************************************************************/
 void execPrime( void )
 {
+    HD_PRE_TREATMENT_PRIME_STATE_T priorSubState = currentPrimeState;
     // execute prime sub-mode state machine
     switch ( currentPrimeState )
     {
@@ -293,6 +294,11 @@
     // Prime flags should be handled by now
     resetPrimeFlags();
 
+    if ( priorSubState != currentPrimeState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentPrimeState );
+    }
+
     // Broadcast priming data
     broadcastPrimingStatus();
 }
Index: firmware/App/Modes/Rinseback.c
===================================================================
diff -u -r0a4dcd288d4347b85baaa0b07da568b6add5eac7 -r82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215
--- firmware/App/Modes/Rinseback.c	(.../Rinseback.c)	(revision 0a4dcd288d4347b85baaa0b07da568b6add5eac7)
+++ firmware/App/Modes/Rinseback.c	(.../Rinseback.c)	(revision 82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215)
@@ -281,7 +281,7 @@
 void execRinseback( void )
 {
     rinsebackTimerCtr++;
-
+    RINSEBACK_STATE_T priorSubState = rinsebackState;
     switch ( rinsebackState )
     {
         case RINSEBACK_STOP_INIT_STATE:
@@ -309,6 +309,10 @@
             break;
     }
 
+    if ( priorSubState != rinsebackState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, rinsebackState );
+    }
     // Rinseback flags should be handled by now - reset in case not handled by current state
     resetRinsebackFlags();
 
Index: firmware/App/Modes/SampleWater.c
===================================================================
diff -u -r0a4dcd288d4347b85baaa0b07da568b6add5eac7 -r82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215
--- firmware/App/Modes/SampleWater.c	(.../SampleWater.c)	(revision 0a4dcd288d4347b85baaa0b07da568b6add5eac7)
+++ firmware/App/Modes/SampleWater.c	(.../SampleWater.c)	(revision 82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215)
@@ -87,6 +87,8 @@
 *************************************************************************/
 void execSampleWater( void )
 {
+    SAMPLE_WATER_STATE_T priorSubState = currentSampleWaterState;
+
 #ifndef _RELEASE_
     if ( SW_CONFIG_ENABLE_VALUE == getSoftwareConfigStatus( SW_CONFIG_DISABLE_SAMPLE_WATER ) )
     {
@@ -113,6 +115,11 @@
                 break;
         }
     }
+
+    if ( priorSubState != currentSampleWaterState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentSampleWaterState );
+    }
 }
 
 /*********************************************************************//**
Index: firmware/App/Modes/SelfTests.c
===================================================================
diff -u -r660876bca7ae34f862ae9cc6feef9a30ec02fe94 -r82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215
--- firmware/App/Modes/SelfTests.c	(.../SelfTests.c)	(revision 660876bca7ae34f862ae9cc6feef9a30ec02fe94)
+++ firmware/App/Modes/SelfTests.c	(.../SelfTests.c)	(revision 82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215)
@@ -288,6 +288,8 @@
  *************************************************************************/
 void execNoCartSelfTests( void )
 {
+    NO_CART_SELF_TESTS_STATE_T priorSubState = currentNoCartSelfTestsState;
+
     // execute no cartridge self-tests state machine
     switch ( currentNoCartSelfTestsState )
     {
@@ -335,6 +337,10 @@
     // Self-tests flags should be handled by now, reset if flags not handled with current state
     resetSelfTestsFlags();
 
+    if ( priorSubState != currentNoCartSelfTestsState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentNoCartSelfTestsState );
+    }
     // Publish current self-test time data
     if ( calcTimeSince( selfTestPreviousPublishDataTime ) >= SELF_TEST_TIME_DATA_PUB_INTERVAL )
     {
@@ -415,6 +421,8 @@
  *************************************************************************/
 void execDrySelfTests( void )
 {
+    DRY_SELF_TESTS_STATE_T priorSubState = currentDrySelfTestsState;
+
     // execute dry self-tests state machine
     switch ( currentDrySelfTestsState )
     {
@@ -511,6 +519,10 @@
     // Self-tests flags should be handled by now, reset if flags not handled with current state
     resetSelfTestsFlags();
 
+    if ( priorSubState != currentDrySelfTestsState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentDrySelfTestsState );
+    }
     // Publish current self-test time data
     if ( calcTimeSince( selfTestPreviousPublishDataTime ) >= SELF_TEST_TIME_DATA_PUB_INTERVAL )
     {
@@ -589,6 +601,8 @@
  *************************************************************************/
 void execWetSelfTests( void )
 {
+    WET_SELF_TESTS_STATE_T priorSubState = currentWetSelfTestsState;
+
 #ifndef _RELEASE_
     if ( getSoftwareConfigStatus( SW_CONFIG_DISABLE_WET_SELF_TEST ) == SW_CONFIG_ENABLE_VALUE )
     {
@@ -658,6 +672,11 @@
 
     // Self-tests flags should be handled by now, reset if flags not handled with current state
     resetSelfTestsFlags();
+
+    if ( priorSubState != currentWetSelfTestsState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentWetSelfTestsState );
+    }
 }
 
 /*********************************************************************//**
Index: firmware/App/Modes/TreatmentEnd.c
===================================================================
diff -u -r0a4dcd288d4347b85baaa0b07da568b6add5eac7 -r82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215
--- firmware/App/Modes/TreatmentEnd.c	(.../TreatmentEnd.c)	(revision 0a4dcd288d4347b85baaa0b07da568b6add5eac7)
+++ firmware/App/Modes/TreatmentEnd.c	(.../TreatmentEnd.c)	(revision 82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215)
@@ -183,6 +183,7 @@
 void execTreatmentEnd( void )
 {
     txEndTimerCtr++;
+    TREATMENT_END_STATE_T priorSubState = treatmentEndState;
 
     switch ( treatmentEndState )
     {
@@ -199,6 +200,10 @@
             break;
     }
 
+    if ( priorSubState != treatmentEndState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, treatmentEndState );
+    }
     // Re-circulate flags should be handled by now - reset in case not handled by current state
     resetTreatmentEndFlags();
 }
Index: firmware/App/Modes/TreatmentRecirc.c
===================================================================
diff -u -r0a4dcd288d4347b85baaa0b07da568b6add5eac7 -r82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215
--- firmware/App/Modes/TreatmentRecirc.c	(.../TreatmentRecirc.c)	(revision 0a4dcd288d4347b85baaa0b07da568b6add5eac7)
+++ firmware/App/Modes/TreatmentRecirc.c	(.../TreatmentRecirc.c)	(revision 82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215)
@@ -191,6 +191,7 @@
 {
     // Count time in this sub-mode
     recircTimerCtr++;
+    TREATMENT_RECIRC_STATE_T priorSubState = treatmentRecircState;
 
     switch ( treatmentRecircState )
     {
@@ -207,6 +208,10 @@
             break;
     }
 
+    if ( priorSubState != treatmentRecircState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, treatmentRecircState );
+    }
     // Re-circulate flags should be handled by now - reset in case not handled by current state
     resetTreatmentRecircFlags();
 
Index: firmware/App/Modes/TreatmentStop.c
===================================================================
diff -u -r0a4dcd288d4347b85baaa0b07da568b6add5eac7 -r82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215
--- firmware/App/Modes/TreatmentStop.c	(.../TreatmentStop.c)	(revision 0a4dcd288d4347b85baaa0b07da568b6add5eac7)
+++ firmware/App/Modes/TreatmentStop.c	(.../TreatmentStop.c)	(revision 82b7c4c94b0f8b3f8a3d3d2e41384a7a7d497215)
@@ -218,6 +218,7 @@
  *************************************************************************/
 void execTreatmentStop( void )
 {
+    TREATMENT_STOP_STATE_T priorSubState = currentTxStopState;
     // Execute treatment stop sub-mode state machine
     switch ( currentTxStopState )
     {
@@ -242,6 +243,10 @@
             break;
     }
 
+    if ( priorSubState != currentTxStopState )
+    {
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentTxStopState );
+    }
     // Broadcast treatment stop status
     publishTreatmentStopData();
 }