Index: firmware/App/Services/Messaging.c
===================================================================
diff -u -rcd1161514dbaff9e5b222931fff99618e39fd7ec -r84b54a6a2e4478c49853f461b8e1ba560441f147
--- firmware/App/Services/Messaging.c	(.../Messaging.c)	(revision cd1161514dbaff9e5b222931fff99618e39fd7ec)
+++ firmware/App/Services/Messaging.c	(.../Messaging.c)	(revision 84b54a6a2e4478c49853f461b8e1ba560441f147)
@@ -7,8 +7,8 @@
 *
 * @file    Messaging.c
 *
-* @author  (last)      Dara Navaei
-* @date    (last)      27-May-2026
+* @author  (last)      Michael Garthwaite
+* @date    (last)      11-Jun-2026
 *
 * @author  (original)  Vinayakam Mani
 * @date    (original)  07-Aug-2024
@@ -60,6 +60,7 @@
 #include "StateFlushFilterDefeatured.h"
 #include "StateFlushPermeate.h"
 #include "StateInletPressureCheck.h"
+#include "SubstitutionPump.h"
 #include "SystemCommDD.h"
 #include "Temperature.h"
 #include "TestSupport.h"
@@ -291,6 +292,9 @@
     { MSG_ID_FP_CONDUCTIVITY_SENSOR_VERSION_REQUEST,                                &testHandleConductivitySensorVersionRequest },
     { MSG_ID_DD_TEMPERATURE_SENSOR_FILTERED_TEMP_OVERRIDE_REQUEST,                  &testDDTemperatureSensorFilteredReadingsOverride },
     { MSG_ID_FP_SET_RECOVERY_VALVES_REQUEST,                                        &testIOFPSetValveRecoveryConfig },
+    { MSG_ID_DD_SUBSTITUTION_PUMP_START_STOP_OVERRIDE_REQUEST,                      &testSubstitutionPumpStartStopOverride },
+    { MSG_ID_DD_SUBSTITUTION_PUMP_BROADCAST_INTERVAL_OVERRIDE_REQUEST,              &testSubstitutionPumpDataPublishIntervalOverride },
+    { MSG_ID_DD_SUBSTITUTION_PUMP_TARGET_RATE_OVERRIDE_REQUEST,                    &testSubstitutionPumpTargetRateOverride },
 };
 
 /// Calculation for number of entries in the incoming message function handler look-up table.