diff --git a/bacnet-stack/demo/object/bo.c b/bacnet-stack/demo/object/bo.c
index 69491457..41ebaddc 100644
--- a/bacnet-stack/demo/object/bo.c
+++ b/bacnet-stack/demo/object/bo.c
@@ -287,11 +287,11 @@ int Binary_Output_Encode_Property_APDU(
                 if (array_index <= BACNET_MAX_PRIORITY) {
                     if (Binary_Output_Level[object_index][array_index - 1] ==
                         BINARY_NULL)
-                        len = encode_application_null(&apdu[apdu_len]);
+                        apdu_len = encode_application_null(&apdu[apdu_len]);
                     else {
                         present_value =
                             Binary_Output_Level[object_index][array_index - 1];
-                        len =
+                        apdu_len =
                             encode_application_enumerated(&apdu[apdu_len],
                             present_value);
                     }
diff --git a/bacnet-stack/demo/object/bv.c b/bacnet-stack/demo/object/bv.c
index 4f5770b2..c4f2d249 100644
--- a/bacnet-stack/demo/object/bv.c
+++ b/bacnet-stack/demo/object/bv.c
@@ -278,11 +278,11 @@ int Binary_Value_Encode_Property_APDU(
                 if (array_index <= BACNET_MAX_PRIORITY) {
                     if (Binary_Value_Level[object_index][array_index] ==
                         BINARY_NULL)
-                        len = encode_application_null(&apdu[apdu_len]);
+                        apdu_len = encode_application_null(&apdu[apdu_len]);
                     else {
                         present_value =
                             Binary_Value_Level[object_index][array_index];
-                        len =
+                        apdu_len =
                             encode_application_enumerated(&apdu[apdu_len],
                             present_value);
                     }
diff --git a/bacnet-stack/ports/bdk-atxx4-mstp/bo.c b/bacnet-stack/ports/bdk-atxx4-mstp/bo.c
index e78c33d6..72338860 100644
--- a/bacnet-stack/ports/bdk-atxx4-mstp/bo.c
+++ b/bacnet-stack/ports/bdk-atxx4-mstp/bo.c
@@ -352,9 +352,9 @@ int Binary_Output_Encode_Property_APDU(
                     present_value =
                         Binary_Output_Level[object_index][array_index - 1];
                     if (present_value == BINARY_NULL) {
-                        len = encode_application_null(&apdu[apdu_len]);
+                        apdu_len = encode_application_null(&apdu[apdu_len]);
                     } else {
-                        len =
+                        apdu_len =
                             encode_application_enumerated(&apdu[apdu_len],
                             present_value);
                     }