diff --git a/bacnet-stack/ports/at91sam7s/device.c b/bacnet-stack/ports/at91sam7s/device.c
index 370a4732..633b40a3 100644
--- a/bacnet-stack/ports/at91sam7s/device.c
+++ b/bacnet-stack/ports/at91sam7s/device.c
@@ -238,6 +238,7 @@ bool Device_Object_List_Identifier(
 /* return the length of the apdu encoded or -1 for error */
 int Device_Encode_Property_APDU(
     uint8_t * apdu,
+    uint32_t object_instance,
     BACNET_PROPERTY_ID property,
     int32_t array_index,
     BACNET_ERROR_CLASS * error_class,
@@ -254,6 +255,7 @@ int Device_Encode_Property_APDU(
     BACNET_TIME local_time;
     BACNET_DATE local_date;
 
+    object_instance = object_instance;
     /* FIXME: change the hardcoded names to suit your application */
     switch (property) {
         case PROP_OBJECT_IDENTIFIER:
diff --git a/bacnet-stack/ports/at91sam7s/h_rp.c b/bacnet-stack/ports/at91sam7s/h_rp.c
index 341f61ab..482b174f 100644
--- a/bacnet-stack/ports/at91sam7s/h_rp.c
+++ b/bacnet-stack/ports/at91sam7s/h_rp.c
@@ -66,7 +66,8 @@ int Encode_Property_APDU(
         case OBJECT_DEVICE:
             if (Device_Valid_Object_Instance_Number(object_instance)) {
                 apdu_len =
-                    Device_Encode_Property_APDU(&apdu[0], property,
+                    Device_Encode_Property_APDU(&apdu[0], 
+                    object_instance, property,
                     array_index, error_class, error_code);
             }
             break;
diff --git a/bacnet-stack/ports/atmega168/device.c b/bacnet-stack/ports/atmega168/device.c
index c291e3f7..846fafd2 100644
--- a/bacnet-stack/ports/atmega168/device.c
+++ b/bacnet-stack/ports/atmega168/device.c
@@ -164,6 +164,7 @@ bool Device_Object_List_Identifier(
 /* return the length of the apdu encoded or -1 for error */
 int Device_Encode_Property_APDU(
     uint8_t * apdu,
+    uint32_t object_instance,
     BACNET_PROPERTY_ID property,
     int32_t array_index,
     BACNET_ERROR_CLASS * error_class,
@@ -178,6 +179,7 @@ int Device_Encode_Property_APDU(
     uint32_t instance = 0;
     unsigned count = 0;
 
+    object_instance = object_instance;
     /* FIXME: change the hardcoded names to suit your application */
     switch (property) {
         case PROP_OBJECT_IDENTIFIER:
diff --git a/bacnet-stack/ports/atmega168/h_rp.c b/bacnet-stack/ports/atmega168/h_rp.c
index cf6475db..00171b26 100644
--- a/bacnet-stack/ports/atmega168/h_rp.c
+++ b/bacnet-stack/ports/atmega168/h_rp.c
@@ -57,7 +57,9 @@ int Encode_Property_APDU(
             if (Device_Valid_Object_Instance_Number(rp_data->object_instance)) {
                 apdu_len =
                     Device_Encode_Property_APDU(&apdu[0],
-                    rp_data->object_property, rp_data->array_index,
+                    rp_data->object_instance,
+                    rp_data->object_property, 
+                    rp_data->array_index,
                     error_class, error_code);
             }
             break;
diff --git a/bacnet-stack/ports/atmega8/device.c b/bacnet-stack/ports/atmega8/device.c
index bbf7272b..b788480b 100644
--- a/bacnet-stack/ports/atmega8/device.c
+++ b/bacnet-stack/ports/atmega8/device.c
@@ -170,6 +170,7 @@ bool Device_Object_List_Identifier(
 /* return the length of the apdu encoded or -1 for error */
 int Device_Encode_Property_APDU(
     uint8_t * apdu,
+    uint32_t object_instance,
     BACNET_PROPERTY_ID property,
     int32_t array_index,
     BACNET_ERROR_CLASS * error_class,
@@ -184,6 +185,7 @@ int Device_Encode_Property_APDU(
     uint32_t instance = 0;
     unsigned count = 0;
 
+    object_instance = object_instance;
     /* FIXME: change the hardcoded names to suit your application */
     switch (property) {
         case PROP_OBJECT_IDENTIFIER:
diff --git a/bacnet-stack/ports/atmega8/h_rp.c b/bacnet-stack/ports/atmega8/h_rp.c
index 94f0f423..419b6279 100644
--- a/bacnet-stack/ports/atmega8/h_rp.c
+++ b/bacnet-stack/ports/atmega8/h_rp.c
@@ -61,7 +61,9 @@ int Encode_Property_APDU(
             if (Device_Valid_Object_Instance_Number(rp_data->object_instance)) {
                 apdu_len =
                     Device_Encode_Property_APDU(&apdu[0],
-                    rp_data->object_property, rp_data->array_index,
+                    rp_data->object_instance,
+                    rp_data->object_property, 
+                    rp_data->array_index,
                     error_class, error_code);
             }
             break;
diff --git a/bacnet-stack/ports/bdk-atxx4-mstp/device.c b/bacnet-stack/ports/bdk-atxx4-mstp/device.c
index a48c8da4..3bbfd826 100644
--- a/bacnet-stack/ports/bdk-atxx4-mstp/device.c
+++ b/bacnet-stack/ports/bdk-atxx4-mstp/device.c
@@ -308,6 +308,7 @@ bool Device_Object_List_Identifier(
 /* return the length of the apdu encoded or -1 for error */
 int Device_Encode_Property_APDU(
     uint8_t * apdu,
+    uint32_t object_instance,
     BACNET_PROPERTY_ID property,
     int32_t array_index,
     BACNET_ERROR_CLASS * error_class,
@@ -322,6 +323,7 @@ int Device_Encode_Property_APDU(
     uint32_t instance = 0;
     unsigned count = 0;
 
+    object_instance = object_instance;
     /* FIXME: change the hardcoded names to suit your application */
     switch (property) {
         case PROP_OBJECT_IDENTIFIER:
diff --git a/bacnet-stack/ports/bdk-atxx4-mstp/h_rp.c b/bacnet-stack/ports/bdk-atxx4-mstp/h_rp.c
index abec7608..414518e4 100644
--- a/bacnet-stack/ports/bdk-atxx4-mstp/h_rp.c
+++ b/bacnet-stack/ports/bdk-atxx4-mstp/h_rp.c
@@ -66,7 +66,8 @@ int Encode_Property_APDU(
         case OBJECT_DEVICE:
             if (Device_Valid_Object_Instance_Number(object_instance)) {
                 apdu_len =
-                    Device_Encode_Property_APDU(&apdu[0], property,
+                    Device_Encode_Property_APDU(&apdu[0], 
+                    object_instance, property,
                     array_index, error_class, error_code);
             }
             break;
diff --git a/bacnet-stack/ports/pic18f6720/device.c b/bacnet-stack/ports/pic18f6720/device.c
index 4cdf7c2c..f6941f8e 100644
--- a/bacnet-stack/ports/pic18f6720/device.c
+++ b/bacnet-stack/ports/pic18f6720/device.c
@@ -242,6 +242,7 @@ bool Device_Object_List_Identifier(
 /* return the length of the apdu encoded or -1 for error */
 int Device_Encode_Property_APDU(
     uint8_t * apdu,
+    uint32_t object_instance,
     BACNET_PROPERTY_ID property,
     int32_t array_index,
     BACNET_ERROR_CLASS * error_class,
@@ -261,6 +262,7 @@ int Device_Encode_Property_APDU(
     char string_buffer[24];
     int16_t TimeZone = 0;
 
+    object_instance = object_instance;
     /* FIXME: change the hardcoded names to suit your application */
     switch (property) {
         case PROP_OBJECT_IDENTIFIER:
diff --git a/bacnet-stack/ports/pic18f6720/h_rp.c b/bacnet-stack/ports/pic18f6720/h_rp.c
index 3f0f789a..6fcc38ee 100644
--- a/bacnet-stack/ports/pic18f6720/h_rp.c
+++ b/bacnet-stack/ports/pic18f6720/h_rp.c
@@ -93,6 +93,7 @@ void handler_read_property(
             if (Device_Valid_Object_Instance_Number(data.object_instance)) {
                 len =
                     Device_Encode_Property_APDU(&Temp_Buf[0],
+                    data.object_instance,
                     data.object_property, data.array_index, &error_class,
                     &error_code);
                 if (len >= 0) {