diff --git a/CHANGELOG.md b/CHANGELOG.md
index 16aa26c5..ea2f1251 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ The git repositories are hosted at the following sites:
 
 ### Security
 
+- Fix [bug#80] npdu_decode via deprecation (#447)
 - Fix [bug#79] out of bounds jump in h_apdu.c:apdu_handler (#446)
 
 ### Fixed
diff --git a/apps/initrouter/main.c b/apps/initrouter/main.c
index 763e960d..948693bf 100644
--- a/apps/initrouter/main.c
+++ b/apps/initrouter/main.c
@@ -185,7 +185,7 @@ static void My_NPDU_Handler(BACNET_ADDRESS *src, /* source address */
     BACNET_ADDRESS dest = { 0 };
     BACNET_NPDU_DATA npdu_data = { 0 };
 
-    apdu_offset = npdu_decode(&pdu[0], &dest, src, &npdu_data);
+    apdu_offset = bacnet_npdu_decode(pdu, pdu_len, &dest, src, &npdu_data);
     if (npdu_data.network_layer_message) {
         if (apdu_offset <= pdu_len) {
             My_Router_Handler(src, &npdu_data, &pdu[apdu_offset],
diff --git a/apps/mstpcap/main.c b/apps/mstpcap/main.c
index 53f6ed7b..8d127cd3 100644
--- a/apps/mstpcap/main.c
+++ b/apps/mstpcap/main.c
@@ -162,7 +162,7 @@ static void mstp_monitor_i_am(uint8_t mac, uint8_t *pdu, uint16_t pdu_len)
 
     if (pdu[0] == BACNET_PROTOCOL_VERSION) {
         MSTP_Fill_BACnet_Address(&src, mac);
-        apdu_offset = npdu_decode(&pdu[0], &dest, &src, &npdu_data);
+        apdu_offset = bacnet_npdu_decode(pdu, pdu_len, &dest, &src, &npdu_data);
         if ((!npdu_data.network_layer_message) && (apdu_offset > 0) &&
             (apdu_offset < pdu_len) && (src.net == 0)) {
             apdu_len = pdu_len - apdu_offset;
diff --git a/apps/netnumis/main.c b/apps/netnumis/main.c
index d3af0a3b..d7337f4b 100644
--- a/apps/netnumis/main.c
+++ b/apps/netnumis/main.c
@@ -149,7 +149,7 @@ static void My_NPDU_Handler(BACNET_ADDRESS *src, /* source address */
     BACNET_ADDRESS dest = { 0 };
     BACNET_NPDU_DATA npdu_data = { 0 };
 
-    apdu_offset = npdu_decode(&pdu[0], &dest, src, &npdu_data);
+    apdu_offset = bacnet_npdu_decode(pdu, pdu_len, &dest, src, &npdu_data);
     if (npdu_data.network_layer_message) {
         My_Router_Handler(src, &npdu_data, &pdu[apdu_offset],
             (uint16_t)(pdu_len - apdu_offset));
diff --git a/apps/router-ipv6/main.c b/apps/router-ipv6/main.c
index e5007f71..480923a9 100644
--- a/apps/router-ipv6/main.c
+++ b/apps/router-ipv6/main.c
@@ -945,7 +945,7 @@ static void my_routing_npdu_handler(
     if (!pdu) {
         /* no packet */
     } else if (pdu[0] == BACNET_PROTOCOL_VERSION) {
-        apdu_offset = npdu_decode(&pdu[0], &dest, src, &npdu_data);
+        apdu_offset = bacnet_npdu_decode(pdu, pdu_len, &dest, src, &npdu_data);
         if (apdu_offset <= 0) {
             fprintf(stderr, "NPDU: Decoding failed; Discarded!\n");
         } else if (npdu_data.network_layer_message) {
diff --git a/apps/router-mstp/main.c b/apps/router-mstp/main.c
index ab5ea450..5f1073af 100644
--- a/apps/router-mstp/main.c
+++ b/apps/router-mstp/main.c
@@ -943,7 +943,7 @@ static void my_routing_npdu_handler(
     if (!pdu) {
         /* no packet */
     } else if (pdu[0] == BACNET_PROTOCOL_VERSION) {
-        apdu_offset = npdu_decode(&pdu[0], &dest, src, &npdu_data);
+        apdu_offset = bacnet_npdu_decode(pdu, pdu_len, &dest, src, &npdu_data);
         if (apdu_offset <= 0) {
             fprintf(stderr, "NPDU: Decoding failed; Discarded!\n");
         } else if (npdu_data.network_layer_message) {
diff --git a/apps/router/main.c b/apps/router/main.c
index ba2e9fa8..8a7624cf 100644
--- a/apps/router/main.c
+++ b/apps/router/main.c
@@ -766,7 +766,8 @@ uint16_t process_msg(BACMSG *msg, MSG_DATA *data, uint8_t **buff)
 
     memmove(data, msg->data, sizeof(MSG_DATA));
 
-    apdu_offset = npdu_decode(data->pdu, &data->dest, &addr, &npdu_data);
+    apdu_offset = bacnet_npdu_decode(data->pdu, data->pdu_len, &data->dest,
+        &addr, &npdu_data);
     apdu_len = data->pdu_len - apdu_offset;
 
     srcport = find_snet(msg->origin);
diff --git a/apps/router/network_layer.c b/apps/router/network_layer.c
index d0dc3884..862fad5a 100644
--- a/apps/router/network_layer.c
+++ b/apps/router/network_layer.c
@@ -45,7 +45,8 @@ uint16_t process_network_message(BACMSG *msg, MSG_DATA *data, uint8_t **buff)
 
     memmove(data, msg->data, sizeof(MSG_DATA));
 
-    apdu_offset = npdu_decode(data->pdu, &data->dest, NULL, &npdu_data);
+    apdu_offset = bacnet_npdu_decode(data->pdu, data->pdu_len, &data->dest,
+        NULL, &npdu_data);
     apdu_len = data->pdu_len - apdu_offset;
 
     srcport = find_snet(msg->origin);
diff --git a/apps/whatisnetnum/main.c b/apps/whatisnetnum/main.c
index 60e7a5ed..3f0d17bb 100644
--- a/apps/whatisnetnum/main.c
+++ b/apps/whatisnetnum/main.c
@@ -134,7 +134,7 @@ static void My_NPDU_Handler(BACNET_ADDRESS *src, /* source address */
     BACNET_ADDRESS dest = { 0 };
     BACNET_NPDU_DATA npdu_data = { 0 };
 
-    apdu_offset = npdu_decode(&pdu[0], &dest, src, &npdu_data);
+    apdu_offset = bacnet_npdu_decode(pdu, pdu_len, &dest, src, &npdu_data);
     if (npdu_data.network_layer_message) {
         My_Router_Handler(src, &npdu_data, &pdu[apdu_offset],
             (uint16_t)(pdu_len - apdu_offset));
diff --git a/apps/whoisrouter/main.c b/apps/whoisrouter/main.c
index c6c2d872..6db782bf 100644
--- a/apps/whoisrouter/main.c
+++ b/apps/whoisrouter/main.c
@@ -132,7 +132,7 @@ static void My_NPDU_Handler(BACNET_ADDRESS *src, /* source address */
     BACNET_ADDRESS dest = { 0 };
     BACNET_NPDU_DATA npdu_data = { 0 };
 
-    apdu_offset = npdu_decode(&pdu[0], &dest, src, &npdu_data);
+    apdu_offset = bacnet_npdu_decode(pdu, pdu_len, &dest, src, &npdu_data);
     if (npdu_data.network_layer_message) {
         My_Router_Handler(src, &npdu_data, &pdu[apdu_offset],
             (uint16_t)(pdu_len - apdu_offset));
diff --git a/ports/at91sam7s/dlmstp.c b/ports/at91sam7s/dlmstp.c
index 62fc7e88..607a8230 100644
--- a/ports/at91sam7s/dlmstp.c
+++ b/ports/at91sam7s/dlmstp.c
@@ -245,8 +245,8 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the request data */
     request.address.mac[0] = src_address;
     request.address.mac_len = 1;
-    offset = npdu_decode(
-        &request_pdu[0], NULL, &request.address, &request.npdu_data);
+    offset = bacnet_npdu_decode(request_pdu, request_pdu_len, NULL,
+        &request.address, &request.npdu_data);
     if (request.npdu_data.network_layer_message) {
         return false;
     }
@@ -263,7 +263,8 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the reply data */
     reply.address.mac[0] = dest_address;
     reply.address.mac_len = 1;
-    offset = npdu_decode(&reply_pdu[0], &reply.address, NULL, &reply.npdu_data);
+    offset = bacnet_npdu_decode(
+        reply_pdu, reply_pdu_len, &reply.address, NULL, &reply.npdu_data);
     if (reply.npdu_data.network_layer_message) {
         return false;
     }
diff --git a/ports/bdk-atxx4-mstp/dlmstp.c b/ports/bdk-atxx4-mstp/dlmstp.c
index b0d8e726..750d6bb9 100644
--- a/ports/bdk-atxx4-mstp/dlmstp.c
+++ b/ports/bdk-atxx4-mstp/dlmstp.c
@@ -246,8 +246,8 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the request data */
     request.address.mac[0] = src_address;
     request.address.mac_len = 1;
-    offset = npdu_decode(
-        &request_pdu[0], NULL, &request.address, &request.npdu_data);
+    offset = bacnet_npdu_decode(request_pdu, request_pdu_len, NULL,
+        &request.address, &request.npdu_data);
     if (request.npdu_data.network_layer_message) {
         return false;
     }
@@ -264,7 +264,8 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the reply data */
     reply.address.mac[0] = dest_address;
     reply.address.mac_len = 1;
-    offset = npdu_decode(&reply_pdu[0], &reply.address, NULL, &reply.npdu_data);
+    offset = bacnet_npdu_decode(
+        reply_pdu, reply_pdu_len, &reply.address, NULL, &reply.npdu_data);
     if (reply.npdu_data.network_layer_message) {
         return false;
     }
diff --git a/ports/linux/dlmstp.c b/ports/linux/dlmstp.c
index 0af1a24f..c30dba45 100644
--- a/ports/linux/dlmstp.c
+++ b/ports/linux/dlmstp.c
@@ -192,14 +192,14 @@ void dlmstp_cleanup(void)
     pthread_mutex_lock(&Thread_Mutex);
     run_thread = false;
     pthread_mutex_unlock(&Thread_Mutex);
-    pthread_join (hThread, NULL);
+    pthread_join(hThread, NULL);
     pthread_cond_destroy(&Received_Frame_Flag);
     pthread_cond_destroy(&Receive_Packet_Flag);
     pthread_cond_destroy(&Master_Done_Flag);
     pthread_mutex_destroy(&Received_Frame_Mutex);
     pthread_mutex_destroy(&Receive_Packet_Mutex);
     pthread_mutex_destroy(&Master_Done_Mutex);
-    pthread_mutex_destroy (&Ring_Buffer_Mutex);
+    pthread_mutex_destroy(&Ring_Buffer_Mutex);
 }
 
 /* returns number of bytes sent on success, zero on failure */
@@ -211,7 +211,7 @@ int dlmstp_send_pdu(BACNET_ADDRESS *dest, /* destination address */
     int bytes_sent = 0;
     struct mstp_pdu_packet *pkt;
     unsigned i = 0;
-    pthread_mutex_lock (&Ring_Buffer_Mutex);
+    pthread_mutex_lock(&Ring_Buffer_Mutex);
     pkt = (struct mstp_pdu_packet *)Ringbuf_Data_Peek(&PDU_Queue);
     if (pkt) {
         pkt->data_expecting_reply = npdu_data->data_expecting_reply;
@@ -229,7 +229,7 @@ int dlmstp_send_pdu(BACNET_ADDRESS *dest, /* destination address */
             bytes_sent = pdu_len;
         }
     }
-    pthread_mutex_unlock (&Ring_Buffer_Mutex);
+    pthread_mutex_unlock(&Ring_Buffer_Mutex);
 
     return bytes_sent;
 }
@@ -310,17 +310,18 @@ static void *dlmstp_master_fsm_task(void *pArg)
                 while (run_loop) {
                     /* do nothing while immediate transitioning */
                     run_loop = MSTP_Master_Node_FSM(&MSTP_Port);
-                    pthread_mutex_lock (&Thread_Mutex);
-                    if (!run_thread) run_loop = false;
-                    pthread_mutex_unlock (&Thread_Mutex);
+                    pthread_mutex_lock(&Thread_Mutex);
+                    if (!run_thread)
+                        run_loop = false;
+                    pthread_mutex_unlock(&Thread_Mutex);
                 }
             } else if (MSTP_Port.This_Station < 255) {
                 MSTP_Slave_Node_FSM(&MSTP_Port);
             }
         }
-        pthread_mutex_lock (&Thread_Mutex);
+        pthread_mutex_lock(&Thread_Mutex);
         thread_alive = run_thread;
-        pthread_mutex_unlock (&Thread_Mutex);
+        pthread_mutex_unlock(&Thread_Mutex);
     }
 
     return NULL;
@@ -389,9 +390,9 @@ uint16_t MSTP_Get_Send(
     struct mstp_pdu_packet *pkt;
 
     (void)timeout;
-    pthread_mutex_lock (&Ring_Buffer_Mutex);
+    pthread_mutex_lock(&Ring_Buffer_Mutex);
     if (Ringbuf_Empty(&PDU_Queue)) {
-        pthread_mutex_unlock (&Ring_Buffer_Mutex);
+        pthread_mutex_unlock(&Ring_Buffer_Mutex);
         return 0;
     }
     pkt = (struct mstp_pdu_packet *)Ringbuf_Peek(&PDU_Queue);
@@ -406,7 +407,7 @@ uint16_t MSTP_Get_Send(
             mstp_port->OutputBufferSize, frame_type, pkt->destination_mac,
             mstp_port->This_Station, (uint8_t *)&pkt->buffer[0], pkt->length);
     (void)Ringbuf_Pop(&PDU_Queue, NULL);
-    pthread_mutex_unlock (&Ring_Buffer_Mutex);
+    pthread_mutex_unlock(&Ring_Buffer_Mutex);
 
     return pdu_len;
 }
@@ -438,8 +439,8 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the request data */
     request.address.mac[0] = src_address;
     request.address.mac_len = 1;
-    offset = npdu_decode(
-        &request_pdu[0], NULL, &request.address, &request.npdu_data);
+    offset = bacnet_npdu_decode(request_pdu, request_pdu_len, NULL,
+        &request.address, &request.npdu_data);
     if (request.npdu_data.network_layer_message) {
 #if PRINT_ENABLED
         fprintf(stderr,
@@ -467,7 +468,8 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the reply data */
     reply.address.mac[0] = dest_address;
     reply.address.mac_len = 1;
-    offset = npdu_decode(&reply_pdu[0], &reply.address, NULL, &reply.npdu_data);
+    offset = bacnet_npdu_decode(
+        reply_pdu, reply_pdu_len, &reply.address, NULL, &reply.npdu_data);
     if (reply.npdu_data.network_layer_message) {
 #if PRINT_ENABLED
         fprintf(stderr,
@@ -730,8 +732,8 @@ bool dlmstp_init(char *ifname)
         exit(1);
     }
 
-    pthread_mutex_init (&Ring_Buffer_Mutex, NULL);
-    pthread_mutex_init (&Thread_Mutex, NULL);
+    pthread_mutex_init(&Ring_Buffer_Mutex, NULL);
+    pthread_mutex_init(&Thread_Mutex, NULL);
 
     /* initialize PDU queue */
     Ringbuf_Init(&PDU_Queue, (uint8_t *)&PDU_Buffer,
@@ -825,4 +827,3 @@ int main(int argc, char *argv[])
     return 0;
 }
 #endif
-
diff --git a/ports/linux/dlmstp_linux.c b/ports/linux/dlmstp_linux.c
index ce924f02..6ea4ecb9 100644
--- a/ports/linux/dlmstp_linux.c
+++ b/ports/linux/dlmstp_linux.c
@@ -411,8 +411,8 @@ bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the request data */
     request.address.mac[0] = src_address;
     request.address.mac_len = 1;
-    offset = npdu_decode(
-        &request_pdu[0], NULL, &request.address, &request.npdu_data);
+    offset = bacnet_npdu_decode(request_pdu, request_pdu_len, NULL,
+        &request.address, &request.npdu_data);
     if (request.npdu_data.network_layer_message) {
 #if PRINT_ENABLED
         fprintf(stderr,
@@ -440,7 +440,8 @@ bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the reply data */
     reply.address.mac[0] = dest_address;
     reply.address.mac_len = 1;
-    offset = npdu_decode(&reply_pdu[0], &reply.address, NULL, &reply.npdu_data);
+    offset = bacnet_npdu_decode(
+        reply_pdu, reply_pdu_len, &reply.address, NULL, &reply.npdu_data);
     if (reply.npdu_data.network_layer_message) {
 #if PRINT_ENABLED
         fprintf(stderr,
diff --git a/ports/pic18f6720/mstp.c b/ports/pic18f6720/mstp.c
index eaae855d..adc9fa0d 100644
--- a/ports/pic18f6720/mstp.c
+++ b/ports/pic18f6720/mstp.c
@@ -567,8 +567,8 @@ static bool mstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the request data */
     request.address.mac[0] = src_address;
     request.address.mac_len = 1;
-    offset = npdu_decode(
-        &request_pdu[0], NULL, &request.address, &request.npdu_data);
+    offset = bacnet_npdu_decode(request_pdu, request_pdu_len, NULL,
+        &request.address, &request.npdu_data);
     if (request.npdu_data.network_layer_message) {
         return false;
     }
@@ -585,7 +585,8 @@ static bool mstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the reply data */
     reply.address.mac[0] = dest_address;
     reply.address.mac_len = 1;
-    offset = npdu_decode(&reply_pdu[0], &reply.address, NULL, &reply.npdu_data);
+    offset = bacnet_npdu_decode(
+        reply_pdu, reply_pdu_len, &reply.address, NULL, &reply.npdu_data);
     if (reply.npdu_data.network_layer_message) {
         return false;
     }
@@ -753,9 +754,9 @@ bool MSTP_Master_Node_FSM(volatile struct mstp_port_struct_t *mstp_port)
                             break;
                         case FRAME_TYPE_BACNET_DATA_NOT_EXPECTING_REPLY:
                             if ((mstp_port->DestinationAddress ==
-                                MSTP_BROADCAST_ADDRESS) &&
+                                    MSTP_BROADCAST_ADDRESS) &&
                                 (npdu_confirmed_service(mstp_port->InputBuffer,
-                                mstp_port->DataLength))) {
+                                    mstp_port->DataLength))) {
                                 /* BTL test: verifies that the IUT will quietly
                                    discard any Confirmed-Request-PDU, whose
                                    destination address is a multicast or
diff --git a/ports/pic18f97j60/mstp.c b/ports/pic18f97j60/mstp.c
index b4344c61..f61daad3 100644
--- a/ports/pic18f97j60/mstp.c
+++ b/ports/pic18f97j60/mstp.c
@@ -567,8 +567,8 @@ static bool mstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the request data */
     request.address.mac[0] = src_address;
     request.address.mac_len = 1;
-    offset = npdu_decode(
-        &request_pdu[0], NULL, &request.address, &request.npdu_data);
+    offset = bacnet_npdu_decode(request_pdu, request_pdu_len, NULL,
+        &request.address, &request.npdu_data);
     if (request.npdu_data.network_layer_message) {
         return false;
     }
@@ -585,7 +585,8 @@ static bool mstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the reply data */
     reply.address.mac[0] = dest_address;
     reply.address.mac_len = 1;
-    offset = npdu_decode(&reply_pdu[0], &reply.address, NULL, &reply.npdu_data);
+    offset = bacnet_npdu_decode(
+        reply_pdu, reply_pdu_len, &reply.address, NULL, &reply.npdu_data);
     if (reply.npdu_data.network_layer_message) {
         return false;
     }
@@ -761,9 +762,9 @@ bool MSTP_Master_Node_FSM(volatile struct mstp_port_struct_t *mstp_port)
                             break;
                         case FRAME_TYPE_BACNET_DATA_NOT_EXPECTING_REPLY:
                             if ((mstp_port->DestinationAddress ==
-                                MSTP_BROADCAST_ADDRESS) &&
+                                    MSTP_BROADCAST_ADDRESS) &&
                                 (npdu_confirmed_service(mstp_port->InputBuffer,
-                                mstp_port->DataLength))) {
+                                    mstp_port->DataLength))) {
                                 /* BTL test: verifies that the IUT will quietly
                                    discard any Confirmed-Request-PDU, whose
                                    destination address is a multicast or
diff --git a/ports/stm32f4xx/dlmstp.c b/ports/stm32f4xx/dlmstp.c
index 2a3fac5b..2f8e0683 100644
--- a/ports/stm32f4xx/dlmstp.c
+++ b/ports/stm32f4xx/dlmstp.c
@@ -247,8 +247,8 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the request data */
     request.address.mac[0] = src_address;
     request.address.mac_len = 1;
-    offset = npdu_decode(
-        &request_pdu[0], NULL, &request.address, &request.npdu_data);
+    offset = bacnet_npdu_decode(request_pdu, request_pdu_len, NULL,
+        &request.address, &request.npdu_data);
     if (request.npdu_data.network_layer_message) {
         return false;
     }
@@ -265,7 +265,8 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the reply data */
     reply.address.mac[0] = dest_address;
     reply.address.mac_len = 1;
-    offset = npdu_decode(&reply_pdu[0], &reply.address, NULL, &reply.npdu_data);
+    offset = bacnet_npdu_decode(
+        reply_pdu, reply_pdu_len, &reply.address, NULL, &reply.npdu_data);
     if (reply.npdu_data.network_layer_message) {
         return false;
     }
@@ -582,8 +583,8 @@ static void MSTP_Receive_Frame_FSM(void)
                                 source = SourceAddress;
                                 destination = DestinationAddress;
                                 frame = FrameType;
-                                Frame_Rx_Callback(source, destination, 
-                                    frame, InputBuffer, DataLength);
+                                Frame_Rx_Callback(source, destination, frame,
+                                    InputBuffer, DataLength);
                             }
                             /* wait for the start of the next frame. */
                             Receive_State = MSTP_RECEIVE_STATE_IDLE;
@@ -674,8 +675,8 @@ static void MSTP_Receive_Frame_FSM(void)
                             source = SourceAddress;
                             destination = DestinationAddress;
                             frame = FrameType;
-                            Frame_Rx_Callback(source, destination,
-                                frame, InputBuffer, DataLength);
+                            Frame_Rx_Callback(source, destination, frame,
+                                InputBuffer, DataLength);
                         }
 
                     } else {
diff --git a/ports/win32/dlmstp-mm.c b/ports/win32/dlmstp-mm.c
index 284780a3..6b2dc7e0 100644
--- a/ports/win32/dlmstp-mm.c
+++ b/ports/win32/dlmstp-mm.c
@@ -323,8 +323,8 @@ bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the request data */
     request.address.mac[0] = src_address;
     request.address.mac_len = 1;
-    offset = npdu_decode(
-        &request_pdu[0], NULL, &request.address, &request.npdu_data);
+    offset = bacnet_npdu_decode(request_pdu, request_pdu_len, NULL,
+        &request.address, &request.npdu_data);
     if (request.npdu_data.network_layer_message) {
         return false;
     }
@@ -340,7 +340,8 @@ bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
         request.service_choice = request_pdu[offset + 3];
     /* decode the reply data */
     bacnet_address_copy(&reply.address, dest_address);
-    offset = npdu_decode(&reply_pdu[0], &reply.address, NULL, &reply.npdu_data);
+    offset = bacnet_npdu_decode(
+        reply_pdu, reply_pdu_len, &reply.address, NULL, &reply.npdu_data);
     if (reply.npdu_data.network_layer_message) {
         return false;
     }
diff --git a/ports/win32/dlmstp.c b/ports/win32/dlmstp.c
index 8fccf21c..49f9f91b 100644
--- a/ports/win32/dlmstp.c
+++ b/ports/win32/dlmstp.c
@@ -308,8 +308,8 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the request data */
     request.address.mac[0] = src_address;
     request.address.mac_len = 1;
-    offset = (uint16_t)npdu_decode(
-        &request_pdu[0], NULL, &request.address, &request.npdu_data);
+    offset = (uint16_t)bacnet_npdu_decode(request_pdu, request_pdu_len, NULL,
+        &request.address, &request.npdu_data);
     if (request.npdu_data.network_layer_message) {
         return false;
     }
@@ -325,8 +325,8 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
         request.service_choice = request_pdu[offset + 3];
     /* decode the reply data */
     bacnet_address_copy(&reply.address, dest_address);
-    offset = (uint16_t)npdu_decode(
-        &reply_pdu[0], &reply.address, NULL, &reply.npdu_data);
+    offset = (uint16_t)bacnet_npdu_decode(
+        reply_pdu, reply_pdu_len, &reply.address, NULL, &reply.npdu_data);
     if (reply.npdu_data.network_layer_message) {
         return false;
     }
diff --git a/ports/xplained/dlmstp.c b/ports/xplained/dlmstp.c
index 351d223d..9f51131b 100644
--- a/ports/xplained/dlmstp.c
+++ b/ports/xplained/dlmstp.c
@@ -239,8 +239,8 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the request data */
     request.address.mac[0] = src_address;
     request.address.mac_len = 1;
-    offset = npdu_decode(
-        &request_pdu[0], NULL, &request.address, &request.npdu_data);
+    offset = bacnet_npdu_decode(request_pdu, request_pdu_len, NULL,
+        &request.address, &request.npdu_data);
     if (request.npdu_data.network_layer_message) {
         return false;
     }
@@ -257,7 +257,8 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t *request_pdu,
     /* decode the reply data */
     reply.address.mac[0] = dest_address;
     reply.address.mac_len = 1;
-    offset = npdu_decode(&reply_pdu[0], &reply.address, NULL, &reply.npdu_data);
+    offset = bacnet_npdu_decode(
+        reply_pdu, reply_pdu_len, &reply.address, NULL, &reply.npdu_data);
     if (reply.npdu_data.network_layer_message) {
         return false;
     }
diff --git a/src/bacnet/basic/npdu/h_routed_npdu.c b/src/bacnet/basic/npdu/h_routed_npdu.c
index 69449ce0..ba754b4b 100644
--- a/src/bacnet/basic/npdu/h_routed_npdu.c
+++ b/src/bacnet/basic/npdu/h_routed_npdu.c
@@ -281,7 +281,7 @@ void routing_npdu_handler(
 
     /* only handle the version that we know how to handle */
     if (pdu[0] == BACNET_PROTOCOL_VERSION) {
-        apdu_offset = npdu_decode(&pdu[0], &dest, src, &npdu_data);
+        apdu_offset = bacnet_npdu_decode(pdu, pdu_len, &dest, src, &npdu_data);
         if (apdu_offset <= 0) {
             debug_printf("NPDU: Decoding failed; Discarded!\n");
         } else if (npdu_data.network_layer_message) {
diff --git a/src/bacnet/npdu.h b/src/bacnet/npdu.h
index b1ecaff6..484f2509 100644
--- a/src/bacnet/npdu.h
+++ b/src/bacnet/npdu.h
@@ -27,6 +27,7 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include "bacnet/bacnet_stack_exports.h"
+#include "bacnet/basic/sys/platform.h"
 #include "bacnet/bacdef.h"
 #include "bacnet/bacenum.h"
 
@@ -98,6 +99,7 @@ extern "C" {
         BACNET_NPDU_DATA * dest,
         BACNET_NPDU_DATA * src);
 
+    BACNET_STACK_DEPRECATED("Use bacnet_npdu_decode() instead")
     BACNET_STACK_EXPORT
     int npdu_decode(
         uint8_t * npdu,
diff --git a/test/bacnet/npdu/src/main.c b/test/bacnet/npdu/src/main.c
index 8098b0d4..0e930969 100644
--- a/test/bacnet/npdu/src/main.c
+++ b/test/bacnet/npdu/src/main.c
@@ -42,7 +42,7 @@ static void test_NPDU_Network(void)
     len = npdu_encode_pdu(&pdu[0], &dest, &src, &npdu_data);
     zassert_not_equal(len, 0, NULL);
     /* can we get the info back? */
-    npdu_len = npdu_decode(&pdu[0], &npdu_dest, &npdu_src, &npdu_data);
+    npdu_len = bacnet_npdu_decode(pdu, sizeof(pdu), &npdu_dest, &npdu_src, &npdu_data);
     zassert_not_equal(npdu_len, 0, NULL);
     zassert_equal(npdu_data.data_expecting_reply, data_expecting_reply, NULL);
     zassert_equal(npdu_data.network_layer_message, network_layer_message, NULL);
@@ -95,7 +95,7 @@ static void testNPDU2(void)
     len = npdu_encode_pdu(&pdu[0], &dest, &src, &npdu_data);
     zassert_not_equal(len, 0, NULL);
     /* can we get the info back? */
-    npdu_len = npdu_decode(&pdu[0], &npdu_dest, &npdu_src, &npdu_data);
+    npdu_len = bacnet_npdu_decode(pdu, sizeof(pdu), &npdu_dest, &npdu_src, &npdu_data);
     zassert_not_equal(npdu_len, 0, NULL);
     zassert_equal(npdu_data.data_expecting_reply, data_expecting_reply, NULL);
     zassert_equal(npdu_data.network_layer_message, network_layer_message, NULL);
@@ -160,7 +160,7 @@ static void testNPDU1(void)
     len = npdu_encode_pdu(&pdu[0], &dest, &src, &npdu_data);
     zassert_not_equal(len, 0, NULL);
     /* can we get the info back? */
-    npdu_len = npdu_decode(&pdu[0], &npdu_dest, &npdu_src, &npdu_data);
+    npdu_len = bacnet_npdu_decode(pdu, sizeof(pdu), &npdu_dest, &npdu_src, &npdu_data);
     zassert_not_equal(npdu_len, 0, NULL);
     zassert_equal(npdu_data.data_expecting_reply, data_expecting_reply, NULL);
     zassert_equal(npdu_data.network_layer_message, network_layer_message, NULL);