diff --git a/bacnet-stack/demo/epics/main.c b/bacnet-stack/demo/epics/main.c
index 05f7bfcb..17b0b9d9 100644
--- a/bacnet-stack/demo/epics/main.c
+++ b/bacnet-stack/demo/epics/main.c
@@ -667,7 +667,7 @@ static uint8_t Read_Properties(
 
     if ((pPropList != NULL) && (pPropList[Property_List_Index] != -1)) {
         int prop = pPropList[Property_List_Index];
-        int32_t array_index;
+        uint32_t array_index;
         IsLongArray = false;
         if (Using_Walked_List) {
             if (Walked_List_Length == 0) {
diff --git a/bacnet-stack/demo/handler/h_rpm_a.c b/bacnet-stack/demo/handler/h_rpm_a.c
index eec7a769..0669c966 100644
--- a/bacnet-stack/demo/handler/h_rpm_a.c
+++ b/bacnet-stack/demo/handler/h_rpm_a.c
@@ -228,7 +228,7 @@ void rpm_ack_print_data(
                     (unsigned) listOfProperties->propertyIdentifier);
             }
 #endif
-            if (listOfProperties->propertyArrayIndex != (int32_t) BACNET_ARRAY_ALL) {
+            if (listOfProperties->propertyArrayIndex != BACNET_ARRAY_ALL) {
 #if PRINT_ENABLED
                 fprintf(stdout, "[%d]", listOfProperties->propertyArrayIndex);
 #endif
diff --git a/bacnet-stack/demo/handler/s_rp.c b/bacnet-stack/demo/handler/s_rp.c
index 240f16d3..6cd0dba6 100644
--- a/bacnet-stack/demo/handler/s_rp.c
+++ b/bacnet-stack/demo/handler/s_rp.c
@@ -55,7 +55,7 @@
  * @param array_index [in] Optional: if the Property is an array,
  *   - 0 for the array size
  *   - 1 to n for individual array members
- *   - -1 for the full array to be read.
+ *   - BACNET_ARRAY_ALL (~0) for the full array to be read.
  * @return invoke id of outgoing message, or 0 if device is not bound or no tsm available
  */
 uint8_t Send_Read_Property_Request(
@@ -63,7 +63,7 @@ uint8_t Send_Read_Property_Request(
     BACNET_OBJECT_TYPE object_type,
     uint32_t object_instance,
     BACNET_PROPERTY_ID object_property,
-    int32_t array_index)
+    uint32_t array_index)
 {
     BACNET_ADDRESS dest;
     BACNET_ADDRESS my_address;
diff --git a/bacnet-stack/demo/handler/s_wp.c b/bacnet-stack/demo/handler/s_wp.c
index d6e46192..d65d4b57 100644
--- a/bacnet-stack/demo/handler/s_wp.c
+++ b/bacnet-stack/demo/handler/s_wp.c
@@ -54,7 +54,7 @@ uint8_t Send_Write_Property_Request_Data(
     uint8_t * application_data,
     int application_data_len,
     uint8_t priority,
-    int32_t array_index)
+    uint32_t array_index)
 {
     BACNET_ADDRESS dest;
     BACNET_ADDRESS my_address;
@@ -136,7 +136,9 @@ uint8_t Send_Write_Property_Request_Data(
  * @param object_value [in] The value to be written to the property.
  * @param priority [in] Write priority of 1 (highest) to 16 (lowest)
  * @param array_index [in] Optional: if the Property is an array,
- *        the index from 1 to n for the individual array member to be written.
+ *   - 0 for the array size
+ *   - 1 to n for individual array members
+ *   - BACNET_ARRAY_ALL (~0) for the array value to be ignored (not sent)
  * @return invoke id of outgoing message, or 0 on failure.
  */
 uint8_t Send_Write_Property_Request(
@@ -146,7 +148,7 @@ uint8_t Send_Write_Property_Request(
     BACNET_PROPERTY_ID object_property,
     BACNET_APPLICATION_DATA_VALUE * object_value,
     uint8_t priority,
-    int32_t array_index)
+    uint32_t array_index)
 {
     uint8_t application_data[MAX_APDU] = { 0 };
     int apdu_len = 0, len = 0;
diff --git a/bacnet-stack/include/bacapp.h b/bacnet-stack/include/bacapp.h
index 32de710e..ca119128 100644
--- a/bacnet-stack/include/bacapp.h
+++ b/bacnet-stack/include/bacapp.h
@@ -98,7 +98,7 @@ typedef struct BACnet_Access_Error {
 struct BACnet_Property_Reference;
 typedef struct BACnet_Property_Reference {
     BACNET_PROPERTY_ID propertyIdentifier;
-    int32_t propertyArrayIndex; /* optional */
+    uint32_t propertyArrayIndex; /* optional */
     /* either value or error, but not both.
        Use NULL value to indicate error */
     BACNET_APPLICATION_DATA_VALUE *value;
@@ -110,7 +110,7 @@ typedef struct BACnet_Property_Reference {
 struct BACnet_Property_Value;
 typedef struct BACnet_Property_Value {
     BACNET_PROPERTY_ID propertyIdentifier;
-    int32_t propertyArrayIndex;
+    uint32_t propertyArrayIndex;
     BACNET_APPLICATION_DATA_VALUE value;
     uint8_t priority;
     /* simple linked list */
@@ -123,7 +123,7 @@ typedef struct BACnet_Object_Property_Value {
     BACNET_OBJECT_TYPE object_type;
     uint32_t object_instance;
     BACNET_PROPERTY_ID object_property;
-    int32_t array_index;
+    uint32_t array_index;
     BACNET_APPLICATION_DATA_VALUE *value;
 } BACNET_OBJECT_PROPERTY_VALUE;
 
diff --git a/bacnet-stack/include/bacdef.h b/bacnet-stack/include/bacdef.h
index 8e40fb06..4bfc45c4 100644
--- a/bacnet-stack/include/bacdef.h
+++ b/bacnet-stack/include/bacdef.h
@@ -56,7 +56,7 @@
 /* large BACnet Object Type */
 #define BACNET_MAX_OBJECT (0x3FF)
 /* Array index 0=size of array, n=array element n,  MAX=all array elements */
-#define BACNET_ARRAY_ALL (~(unsigned int)0)
+#define BACNET_ARRAY_ALL (~0UL)
 /* Priority Array for commandable objects */
 #define BACNET_NO_PRIORITY 0
 #define BACNET_MIN_PRIORITY 1
diff --git a/bacnet-stack/include/client.h b/bacnet-stack/include/client.h
index 0a55c533..7f30c13a 100644
--- a/bacnet-stack/include/client.h
+++ b/bacnet-stack/include/client.h
@@ -119,7 +119,7 @@ extern "C" {
         BACNET_OBJECT_TYPE object_type,
         uint32_t object_instance,
         BACNET_PROPERTY_ID object_property,
-        int32_t array_index);
+        uint32_t array_index);
     uint8_t Send_Read_Property_Multiple_Request(
         uint8_t * pdu,
         size_t max_pdu,
@@ -134,7 +134,7 @@ extern "C" {
         BACNET_PROPERTY_ID object_property,
         BACNET_APPLICATION_DATA_VALUE * object_value,
         uint8_t priority,
-        int32_t array_index);
+        uint32_t array_index);
     uint8_t Send_Write_Property_Request_Data(
         uint32_t device_id,
         BACNET_OBJECT_TYPE object_type,
@@ -143,7 +143,7 @@ extern "C" {
         uint8_t * application_data,
         int application_data_len,
         uint8_t priority,
-        int32_t array_index);
+        uint32_t array_index);
 
 /* returns the invoke ID for confirmed request, or 0 if failed */
     uint8_t Send_Reinitialize_Device_Request(
diff --git a/bacnet-stack/include/handlers.h b/bacnet-stack/include/handlers.h
index 5189d744..f921083e 100644
--- a/bacnet-stack/include/handlers.h
+++ b/bacnet-stack/include/handlers.h
@@ -209,18 +209,6 @@ extern "C" {
     void rpm_ack_print_data(
         BACNET_READ_ACCESS_DATA * rpm_data);
 
-    /* Encodes the property APDU and returns the length,
-       or sets the error, and returns -1 */
-    /* resides in h_rp.c */
-    int Encode_Property_APDU(
-        uint8_t * apdu,
-        BACNET_OBJECT_TYPE object_type,
-        uint32_t object_instance,
-        BACNET_PROPERTY_ID property,
-        int32_t array_index,
-        BACNET_ERROR_CLASS * error_class,
-        BACNET_ERROR_CODE * error_code);
-
     void handler_cov_subscribe(
         uint8_t * service_request,
         uint16_t service_len,
diff --git a/bacnet-stack/include/rp.h b/bacnet-stack/include/rp.h
index dc8cf5f4..9ff0eb9c 100644
--- a/bacnet-stack/include/rp.h
+++ b/bacnet-stack/include/rp.h
@@ -43,7 +43,7 @@ typedef struct BACnet_Read_Property_Data {
     BACNET_OBJECT_TYPE object_type;
     uint32_t object_instance;
     BACNET_PROPERTY_ID object_property;
-    int32_t array_index;
+    uint32_t array_index;
     uint8_t *application_data;
     int application_data_len;
     BACNET_ERROR_CLASS error_class;
@@ -55,7 +55,7 @@ struct BACnet_Read_Access_Data;
 
 /** Reads one property for this object type of a given instance.
  * A function template; @see device.c for assignment to object types.
- * @ingroup ObjHelpers 
+ * @ingroup ObjHelpers
  *
  * @param rp_data [in] Pointer to the BACnet_Read_Property_Data structure,
  *                     which is packed with the information from the RP request.
@@ -132,14 +132,14 @@ extern "C" {
 }
 #endif /* __cplusplus */
 /** @defgroup DataShare Data Sharing BIBBs
- * These BIBBs prescribe the BACnet capabilities required to interoperably 
- * perform the data sharing functions enumerated in 22.2.1.1 for the BACnet 
+ * These BIBBs prescribe the BACnet capabilities required to interoperably
+ * perform the data sharing functions enumerated in 22.2.1.1 for the BACnet
  * devices defined therein.
           *//** @defgroup DSRP Data Sharing -Read Property Service (DS-RP)
  * @ingroup DataShare
  * 15.5 ReadProperty Service <br>
- * The ReadProperty service is used by a client BACnet-user to request the 
- * value of one property of one BACnet Object. This service allows read access 
+ * The ReadProperty service is used by a client BACnet-user to request the
+ * value of one property of one BACnet Object. This service allows read access
  * to any property of any object, whether a BACnet-defined object or not.
  */
 #endif
diff --git a/bacnet-stack/include/rpm.h b/bacnet-stack/include/rpm.h
index ba1c24a6..5ab2bd5f 100644
--- a/bacnet-stack/include/rpm.h
+++ b/bacnet-stack/include/rpm.h
@@ -41,7 +41,7 @@
 #include "bacapp.h"
 
 /*
- * Bundle together commonly used data items for convenience when calling 
+ * Bundle together commonly used data items for convenience when calling
  * rpm helper functions.
  */
 
@@ -49,7 +49,7 @@ typedef struct BACnet_RPM_Data {
     BACNET_OBJECT_TYPE object_type;
     uint32_t object_instance;
     BACNET_PROPERTY_ID object_property;
-    int32_t array_index;
+    uint32_t array_index;
     BACNET_ERROR_CLASS error_class;
     BACNET_ERROR_CODE error_code;
 } BACNET_RPM_DATA;
@@ -66,7 +66,7 @@ typedef struct BACnet_Read_Access_Data {
 /** Fetches the lists of properties (array of BACNET_PROPERTY_ID's) for this
  *  object type, grouped by Required, Optional, and Proprietary.
  * A function template; @see device.c for assignment to object types.
- * @ingroup ObjHelpers 
+ * @ingroup ObjHelpers
  *
  * @param pRequired [out] Pointer reference for the list of Required properties.
  * @param pOptional [out] Pointer reference for the list of Optional properties.
@@ -118,7 +118,7 @@ extern "C" {
     int rpm_encode_apdu_object_property(
         uint8_t * apdu,
         BACNET_PROPERTY_ID object_property,
-        int32_t array_index);
+        uint32_t array_index);
 
     int rpm_encode_apdu_object_end(
         uint8_t * apdu);
@@ -158,7 +158,7 @@ extern "C" {
     int rpm_ack_encode_apdu_object_property(
         uint8_t * apdu,
         BACNET_PROPERTY_ID object_property,
-        int32_t array_index);
+        uint32_t array_index);
 
     int rpm_ack_encode_apdu_object_property_value(
         uint8_t * apdu,
@@ -186,7 +186,7 @@ extern "C" {
         uint8_t * apdu,
         unsigned apdu_len,
         BACNET_PROPERTY_ID * object_property,
-        int32_t * array_index);
+        uint32_t * array_index);
 #ifdef TEST
 #include "ctest.h"
     int rpm_decode_apdu(
@@ -215,13 +215,13 @@ extern "C" {
 /** @defgroup DSRPM Data Sharing -Read Property Multiple Service (DS-RPM)
  * @ingroup DataShare
  * 15.7 ReadPropertyMultiple Service <br>
- * The ReadPropertyMultiple service is used by a client BACnet-user to request 
- * the values of one or more specified properties of one or more BACnet Objects. 
- * This service allows read access to any property of any object, whether a 
- * BACnet-defined object or not. The user may read a single property of a single 
- * object, a list of properties of a single object, or any number of properties 
- * of any number of objects. 
- * A 'Read Access Specification' with the property identifier ALL can be used to 
+ * The ReadPropertyMultiple service is used by a client BACnet-user to request
+ * the values of one or more specified properties of one or more BACnet Objects.
+ * This service allows read access to any property of any object, whether a
+ * BACnet-defined object or not. The user may read a single property of a single
+ * object, a list of properties of a single object, or any number of properties
+ * of any number of objects.
+ * A 'Read Access Specification' with the property identifier ALL can be used to
  * learn the implemented properties of an object along with their values.
  */
 #endif
diff --git a/bacnet-stack/include/wp.h b/bacnet-stack/include/wp.h
index 2179468e..9fdcdd2c 100644
--- a/bacnet-stack/include/wp.h
+++ b/bacnet-stack/include/wp.h
@@ -47,7 +47,7 @@ typedef struct BACnet_Write_Property_Data {
     BACNET_OBJECT_TYPE object_type;
     uint32_t object_instance;
     BACNET_PROPERTY_ID object_property;
-    int32_t array_index;        /* use BACNET_ARRAY_ALL when not setting */
+    uint32_t array_index; /* use BACNET_ARRAY_ALL when not setting */
     uint8_t application_data[MAX_APDU];
     int application_data_len;
     uint8_t priority;   /* use BACNET_NO_PRIORITY if no priority */
@@ -58,7 +58,7 @@ typedef struct BACnet_Write_Property_Data {
 /** Attempts to write a new value to one property for this object type
  *  of a given instance.
  * A function template; @see device.c for assignment to object types.
- * @ingroup ObjHelpers 
+ * @ingroup ObjHelpers
  *
  * @param wp_data [in] Pointer to the BACnet_Write_Property_Data structure,
  *                     which is packed with the information from the WP request.
@@ -105,12 +105,12 @@ extern "C" {
 /** @defgroup DSWP Data Sharing - Write Property Service (DS-WP)
  * @ingroup DataShare
  * 15.9 WriteProperty Service <br>
- * The WriteProperty service is used by a client BACnet-user to modify the 
- * value of a single specified property of a BACnet object. This service 
- * potentially allows write access to any property of any object, whether a 
- * BACnet-defined object or not. Some implementors may wish to restrict write 
- * access to certain properties of certain objects. In such cases, an attempt 
- * to modify a restricted property shall result in the return of an error of 
- * 'Error Class' PROPERTY and 'Error Code' WRITE_ACCESS_DENIED. 
+ * The WriteProperty service is used by a client BACnet-user to modify the
+ * value of a single specified property of a BACnet object. This service
+ * potentially allows write access to any property of any object, whether a
+ * BACnet-defined object or not. Some implementors may wish to restrict write
+ * access to certain properties of certain objects. In such cases, an attempt
+ * to modify a restricted property shall result in the return of an error of
+ * 'Error Class' PROPERTY and 'Error Code' WRITE_ACCESS_DENIED.
  */
 #endif
diff --git a/bacnet-stack/ports/atmega168/ai.c b/bacnet-stack/ports/atmega168/ai.c
index 3eea933d..c11b7ccb 100644
--- a/bacnet-stack/ports/atmega168/ai.c
+++ b/bacnet-stack/ports/atmega168/ai.c
@@ -94,7 +94,7 @@ int Analog_Input_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
diff --git a/bacnet-stack/ports/atmega168/av.c b/bacnet-stack/ports/atmega168/av.c
index 184b760d..ef0a97c0 100644
--- a/bacnet-stack/ports/atmega168/av.c
+++ b/bacnet-stack/ports/atmega168/av.c
@@ -96,7 +96,7 @@ int Analog_Value_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
diff --git a/bacnet-stack/ports/atmega168/av.h b/bacnet-stack/ports/atmega168/av.h
index 1a31b523..40f84fe8 100644
--- a/bacnet-stack/ports/atmega168/av.h
+++ b/bacnet-stack/ports/atmega168/av.h
@@ -55,7 +55,7 @@ extern "C" {
         uint8_t * apdu,
         uint32_t object_instance,
         BACNET_PROPERTY_ID property,
-        int32_t array_index,
+        uint32_t array_index,
         BACNET_ERROR_CLASS * error_class,
         BACNET_ERROR_CODE * error_code);
 
diff --git a/bacnet-stack/ports/atmega168/bv.c b/bacnet-stack/ports/atmega168/bv.c
index 67b8abf7..48510722 100644
--- a/bacnet-stack/ports/atmega168/bv.c
+++ b/bacnet-stack/ports/atmega168/bv.c
@@ -109,7 +109,7 @@ int Binary_Value_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
diff --git a/bacnet-stack/ports/atmega168/bv.h b/bacnet-stack/ports/atmega168/bv.h
index 784acaff..731f3e48 100644
--- a/bacnet-stack/ports/atmega168/bv.h
+++ b/bacnet-stack/ports/atmega168/bv.h
@@ -60,7 +60,7 @@ extern "C" {
         uint8_t * apdu,
         uint32_t object_instance,
         BACNET_PROPERTY_ID property,
-        int32_t array_index,
+        uint32_t array_index,
         BACNET_ERROR_CLASS * error_class,
         BACNET_ERROR_CODE * error_code);
 
diff --git a/bacnet-stack/ports/atmega168/device.c b/bacnet-stack/ports/atmega168/device.c
index d7eede8b..700a4d3c 100644
--- a/bacnet-stack/ports/atmega168/device.c
+++ b/bacnet-stack/ports/atmega168/device.c
@@ -166,7 +166,7 @@ int Device_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
diff --git a/bacnet-stack/ports/atmega8/ai.c b/bacnet-stack/ports/atmega8/ai.c
index 76cbd213..848482ef 100644
--- a/bacnet-stack/ports/atmega8/ai.c
+++ b/bacnet-stack/ports/atmega8/ai.c
@@ -94,7 +94,7 @@ int Analog_Input_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
diff --git a/bacnet-stack/ports/atmega8/av.c b/bacnet-stack/ports/atmega8/av.c
index 184b760d..ef0a97c0 100644
--- a/bacnet-stack/ports/atmega8/av.c
+++ b/bacnet-stack/ports/atmega8/av.c
@@ -96,7 +96,7 @@ int Analog_Value_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
diff --git a/bacnet-stack/ports/atmega8/bv.c b/bacnet-stack/ports/atmega8/bv.c
index 67b8abf7..48510722 100644
--- a/bacnet-stack/ports/atmega8/bv.c
+++ b/bacnet-stack/ports/atmega8/bv.c
@@ -109,7 +109,7 @@ int Binary_Value_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
diff --git a/bacnet-stack/ports/atmega8/device.c b/bacnet-stack/ports/atmega8/device.c
index c2ce41f8..78151422 100644
--- a/bacnet-stack/ports/atmega8/device.c
+++ b/bacnet-stack/ports/atmega8/device.c
@@ -172,7 +172,7 @@ int Device_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
diff --git a/bacnet-stack/ports/pic18f6720/ai.c b/bacnet-stack/ports/pic18f6720/ai.c
index 64383cdf..62960c7e 100644
--- a/bacnet-stack/ports/pic18f6720/ai.c
+++ b/bacnet-stack/ports/pic18f6720/ai.c
@@ -103,7 +103,7 @@ int Analog_Input_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
diff --git a/bacnet-stack/ports/pic18f6720/av.c b/bacnet-stack/ports/pic18f6720/av.c
index b9f3b96d..302c884b 100644
--- a/bacnet-stack/ports/pic18f6720/av.c
+++ b/bacnet-stack/ports/pic18f6720/av.c
@@ -151,7 +151,7 @@ int Analog_Value_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
@@ -331,8 +331,8 @@ bool Analog_Value_Write_Property(
                     Present_Value[object_index] = level;
                     /* Note: you could set the physical output here if we
                        are the highest priority.
-                       However, if Out of Service is TRUE, then don't set the 
-                       physical output.  This comment may apply to the 
+                       However, if Out of Service is TRUE, then don't set the
+                       physical output.  This comment may apply to the
                        main loop (i.e. check out of service before changing output) */
                     status = true;
                 } else if (priority == 6) {
@@ -357,8 +357,8 @@ bool Analog_Value_Write_Property(
                     /* Note: you could set the physical output here to the next
                        highest priority, or to the relinquish default if no
                        priorities are set.
-                       However, if Out of Service is TRUE, then don't set the 
-                       physical output.  This comment may apply to the 
+                       However, if Out of Service is TRUE, then don't set the
+                       physical output.  This comment may apply to the
                        main loop (i.e. check out of service before changing output) */
                     status = true;
                 } else {
diff --git a/bacnet-stack/ports/pic18f6720/bi.c b/bacnet-stack/ports/pic18f6720/bi.c
index 6b8e2c1a..2109ef0d 100644
--- a/bacnet-stack/ports/pic18f6720/bi.c
+++ b/bacnet-stack/ports/pic18f6720/bi.c
@@ -123,7 +123,7 @@ int Binary_Input_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
diff --git a/bacnet-stack/ports/pic18f6720/bv.c b/bacnet-stack/ports/pic18f6720/bv.c
index d79c192c..a4c40ab7 100644
--- a/bacnet-stack/ports/pic18f6720/bv.c
+++ b/bacnet-stack/ports/pic18f6720/bv.c
@@ -120,7 +120,7 @@ int Binary_Value_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
@@ -244,7 +244,7 @@ bool Binary_Value_Write_Property(
                     Present_Value[object_index] = level;
                     /* Note: you could set the physical output here if we
                        are the highest priority.
-                       However, if Out of Service is TRUE, then don't set the 
+                       However, if Out of Service is TRUE, then don't set the
                        physical output. */
                     status = true;
                 } else if (priority == 6) {
@@ -270,8 +270,8 @@ bool Binary_Value_Write_Property(
                     /* Note: you could set the physical output here to the next
                        highest priority, or to the relinquish default if no
                        priorities are set.
-                       However, if Out of Service is TRUE, then don't set the 
-                       physical output.  This comment may apply to the 
+                       However, if Out of Service is TRUE, then don't set the
+                       physical output.  This comment may apply to the
                        main loop (i.e. check out of service before changing output) */
                     status = true;
                 } else {
diff --git a/bacnet-stack/ports/pic18f6720/device.c b/bacnet-stack/ports/pic18f6720/device.c
index a37e2bf5..fb361162 100644
--- a/bacnet-stack/ports/pic18f6720/device.c
+++ b/bacnet-stack/ports/pic18f6720/device.c
@@ -242,7 +242,7 @@ int Device_Encode_Property_APDU(
     uint8_t * apdu,
     uint32_t object_instance,
     BACNET_PROPERTY_ID property,
-    int32_t array_index,
+    uint32_t array_index,
     BACNET_ERROR_CLASS * error_class,
     BACNET_ERROR_CODE * error_code)
 {
diff --git a/bacnet-stack/src/rpm.c b/bacnet-stack/src/rpm.c
index 4cfbf93e..6b6859bb 100644
--- a/bacnet-stack/src/rpm.c
+++ b/bacnet-stack/src/rpm.c
@@ -81,7 +81,7 @@ int rpm_encode_apdu_object_begin(
 int rpm_encode_apdu_object_property(
     uint8_t * apdu,
     BACNET_PROPERTY_ID object_property,
-    int32_t array_index)
+    uint32_t array_index)
 {
     int apdu_len = 0;   /* total length of the apdu, return value */
 
@@ -344,7 +344,7 @@ int rpm_ack_encode_apdu_object_begin(
 int rpm_ack_encode_apdu_object_property(
     uint8_t * apdu,
     BACNET_PROPERTY_ID object_property,
-    int32_t array_index)
+    uint32_t array_index)
 {
     int apdu_len = 0;   /* total length of the apdu, return value */
 
@@ -457,7 +457,7 @@ int rpm_ack_decode_object_property(
     uint8_t * apdu,
     unsigned apdu_len,
     BACNET_PROPERTY_ID * object_property,
-    int32_t * array_index)
+    uint32_t * array_index)
 {
     unsigned len = 0;
     unsigned tag_len = 0;
@@ -702,7 +702,7 @@ void testReadPropertyMultipleAck(
     BACNET_OBJECT_TYPE object_type = OBJECT_DEVICE;
     uint32_t object_instance = 0;
     BACNET_PROPERTY_ID object_property = PROP_OBJECT_IDENTIFIER;
-    int32_t array_index = 0;
+    uint32_t array_index = 0;
     BACNET_APPLICATION_DATA_VALUE application_data[4] = { {0} };
     BACNET_APPLICATION_DATA_VALUE test_application_data = { 0 };
     uint8_t application_data_buffer[MAX_APDU] = { 0 };
@@ -721,7 +721,6 @@ void testReadPropertyMultipleAck(
        Also check case of storing a backoff point
        (i.e. save enough room for object_end) */
     apdu_len = rpm_ack_encode_apdu_init(&apdu[0], invoke_id);
-
     /* object beginning */
     rpmdata.object_type = OBJECT_DEVICE;
     rpmdata.object_instance = 123;