Index: firmware/App/Services/DDInterface.c
===================================================================
diff -u -r25aeff9e9994d2e7aab3b4e6171c56fdac6a01fe -r81e5d76c3906a8c18be914f5736a796436fd85b5
--- firmware/App/Services/DDInterface.c	(.../DDInterface.c)	(revision 25aeff9e9994d2e7aab3b4e6171c56fdac6a01fe)
+++ firmware/App/Services/DDInterface.c	(.../DDInterface.c)	(revision 81e5d76c3906a8c18be914f5736a796436fd85b5)
@@ -8,7 +8,7 @@
 * @file    DDInterface.c
 *
 * @author  (last)      Varshini Nagabooshanam
-* @date    (last)      15-Jun-2026
+* @date    (last)      19-Aug-2026
 *
 * @author  (original)  Sean Nash
 * @date    (original)  01-Aug-2024
@@ -527,6 +527,36 @@
 
 /*********************************************************************//**
  * @brief
+ * The cmdChangeDialysateTemperature function sends a generate dialysate
+ * command to the DD with a given new dialysate temperature.
+ * @details \b Inputs: none
+ * @details \b Outputs: dialysateDeliveryCmdSet
+ * @details \b Message \b Sent: Continue generate dialysate command w/ new
+ * dialysate temperature.
+ * @param dialTemp Target dialysate temperature in deg C.
+ * @return none
+ *************************************************************************/
+void cmdChangeDialysateTemperature( F32 dialTemp )
+{
+    if ( TRUE == dialysateDeliveryCmdSet.start )
+    {
+        dialysateDeliveryCmdSet.dialTemp = dialTemp;
+
+#ifndef TEST_UI_ONLY
+        sendMessage( MSG_ID_DD_GEN_DIALYSATE_REQUEST_DATA,
+                     COMM_BUFFER_OUT_CAN_TD_2_DD,
+                     (U08*)(&dialysateDeliveryCmdSet),
+                     sizeof( DIALYSATE_DELIVERY_REQ_PAYLOAD_T ) );
+#endif
+    }
+    else
+    {
+        // TODO - s/w fault?
+    }
+}
+
+/*********************************************************************//**
+ * @brief
  * The cmdBypassDialyzer function sends a generate dialysate command to the DD
  * with a given flag indicating whether dialyzer should be bypassed.
  * @details \b Inputs: none
@@ -682,7 +712,8 @@
     {
         dialysateDeliveryCmdSet.substitutionRate = qs;
 #ifndef TEST_UI_ONLY
-        sendMessage( MSG_ID_DD_GEN_DIALYSATE_REQUEST_DATA, COMM_BUFFER_OUT_CAN_TD_2_DD, (U08*)(&dialysateDeliveryCmdSet), sizeof( DIALYSATE_DELIVERY_REQ_PAYLOAD_T ) );
+        sendMessage( MSG_ID_DD_GEN_DIALYSATE_REQUEST_DATA, COMM_BUFFER_OUT_CAN_TD_2_DD,
+                     (U08*)(&dialysateDeliveryCmdSet), sizeof( DIALYSATE_DELIVERY_REQ_PAYLOAD_T ) );
 #endif
     }
     else