diff --git a/Core/Src/sts_cmox_hmac_sha.c b/Core/Src/sts_cmox_hmac_sha.c
index ac73c59..270e9c7 100644
--- a/Core/Src/sts_cmox_hmac_sha.c
+++ b/Core/Src/sts_cmox_hmac_sha.c
@@ -34,7 +34,6 @@ hmac_result_t hmac_result;
 
 uint32_t sts_hmac_verify(void)
 {
-	uint8_t i=0;
 	uint8_t uid[8]="";
 	uint32_t ret=0;
 	hmac_result.ac_pass = 60;
@@ -42,22 +41,13 @@ uint32_t sts_hmac_verify(void)
 	GetUniqueId(uid);
 
 	ret = sts_hmac_sha1((const uint8_t *) mKey, sizeof(mKey), (const uint8_t*)(uid+4), 4, &hmac_result);
-	for (i=0;i<sizeof(Computed_Tag_SHA1); i++) {
-			APP_LOG(TS_OFF,VLEVEL_H,"0x%02x ", hmac_result.hmac_tag[i]);
-	}
 
 	ret = memcmp(hmac_result.hmac_tag, (void *)sts_ac_code, sizeof(sts_ac_code));
 
-	if (ret != 0)
-	{
-		hmac_result.ac_pass  =0U;
-		APP_LOG(TS_OFF, VLEVEL_H, "\r\nHMAC Verify Error \r\n");
-	} else
-	{
-		ret = 0;
-		hmac_result.ac_pass = 1U;
-		APP_LOG(TS_OFF, VLEVEL_H, "\r\nHMAC Verify Success\r\n");
-	}
+	hmac_result.ac_pass  = (ret == 0x0)?1U:0U;
+
+	APP_LOG(TS_OFF, VLEVEL_M, "\r\nHMAC Verify Success = %u \r\n", hmac_result.ac_pass);
+
 	return ret;
 }
 
diff --git a/Core/Src/usart_if.c b/Core/Src/usart_if.c
index d07fa47..1f13f50 100644
--- a/Core/Src/usart_if.c
+++ b/Core/Src/usart_if.c
@@ -127,7 +127,7 @@ UTIL_ADV_TRACE_Status_t vcom_DeInit(void)
 
   /* ##-3- Disable the NVIC for DMA ########################################### */
   /* USER CODE BEGIN 1 */
-  HAL_NVIC_DisableIRQ(DMA1_Channel5_IRQn);
+  HAL_NVIC_DisableIRQ(DMA1_Channel7_IRQn);
 
   return UTIL_ADV_TRACE_OK;
   /* USER CODE END 1 */
diff --git a/LoRaWAN/App/lora_app.c b/LoRaWAN/App/lora_app.c
index 86503ff..73fc2fb 100644
--- a/LoRaWAN/App/lora_app.c
+++ b/LoRaWAN/App/lora_app.c
@@ -322,6 +322,12 @@ static void OnJoinTimerLedEvent(void *context);
 
 static void OnYunhornSTSOORSSWakeUpTimerEvent(void *context);
 
+/**
+  * @brief  Yunhorn STS Heart Beat Periodicity Chagne function
+  * @param  duration of periodicty in ms (1/1000 sec)
+  */
+static void OnYunhornSTSHeartBeatPeriodicityChanged(uint32_t periodicity);
+
 /**
   * @brief  Yunhorn STS AC Code handle Process
   * @param  void
@@ -441,6 +447,10 @@ static UTIL_TIMER_Object_t YunhornSTSRSSWakeUpTimer;
   * @brief Timer to handle the YunHorn STS Sensor Sampling Process
   */
 //static UTIL_TIMER_Object_t YunhornSTSSamplingCheckTimer;
+/**
+  * @brief Timer to handle the YunHorn STS Sensor Heart Beat Process
+  */
+static UTIL_TIMER_Object_t YunhornSTSHeartBeatTimer;
 
 /* USER CODE END PV */
 
@@ -654,6 +664,16 @@ static void OnRxData(LmHandlerAppData_t *appData, LmHandlerRxParams_t *params)
                     break;
                 }
               }
+              DeviceClass_t deviceClass = CLASS_A;
+              LmHandlerGetCurrentClass( &deviceClass );
+              uint8_t	i=0;
+              outbuf[i++] = (uint8_t) 'L';
+              outbuf[i++] = (uint8_t) sts_mtmcode1;
+              outbuf[i++] = (uint8_t) sts_mtmcode2;
+              outbuf[i++] = (uint8_t) sts_version;
+              outbuf[i++] = (uint8_t) (0x41+ deviceClass); //translate to 'A','B','C'
+              STS_SENSOR_Upload_Message(LORAWAN_USER_APP_CTRL_REPLY_PORT, i, outbuf);
+
               break;
             case LORAWAN_USER_APP_PORT:
               if (appData->BufferSize == 1)
@@ -984,8 +1004,9 @@ static void OnJoinRequest(LmHandlerJoinParams_t *joinParams)
 
       STS_LoRa_WAN_Joined = (uint8_t) joinParams->Mode;
 
-      //APP_LOG(TS_OFF, VLEVEL_M,"\r\n STS_LoRa_WAN_Joined = %d \r\n", STS_LoRa_WAN_Joined);
-
+      OnYunhornSTSHeartBeatPeriodicityChanged(HeartBeatPeriodicity);
+      OnTxPeriodicityChanged(TxPeriodicity);
+      APP_LOG(TS_OFF, VLEVEL_L,"\r\n STS_LoRa_WAN_Joined = %s \r\n", (STS_LoRa_WAN_Joined == 1)?"ABP":"OTAA");
     }
     else
     {
@@ -994,6 +1015,7 @@ static void OnJoinRequest(LmHandlerJoinParams_t *joinParams)
 
     APP_LOG(TS_OFF, VLEVEL_H, "###### U/L FRAME:JOIN | DR:%d | PWR:%d\r\n", joinParams->Datarate, joinParams->TxPower);
   }
+  UTIL_SEQ_SetTask((1 << CFG_SEQ_Task_LoRaSendOnTxTimerOrButtonEvent), CFG_SEQ_Prio_0);
   /* USER CODE END OnJoinRequest_1 */
 }
 
@@ -1253,33 +1275,34 @@ static void OnYunhornSTSOORSSWakeUpTimerEvent(void *context)
 }
 
 /**
-  * @brief  Yunhorn STS Sensor Heart Beat Timer callback function
-  * @param  context ptr of STS Sampling Check context
-  */
-/*
-static void OnYunhornSTSHeartBeatTimerEvent(void *context)
+  * @brief  Yunhorn STS  Sensor Live Heart Beat Periodicity/interval Change callback function
+  * @param  context ptr of STS Live Heart Beat context
+  * YL x x x
+  * */
+
+static void OnYunhornSTSHeartBeatPeriodicityChanged(uint32_t periodicity)
 {
-	    if (STS_LoRa_WAN_Joined )
-	    {
+  /* USER CODE BEGIN OnTxPeriodicityChanged_1 */
 
-	    	heart_beat_timer = 1;
-	    	UTIL_SEQ_SetTask((1 << CFG_SEQ_Task_LoRaSendOnTxTimerOrButtonEvent), CFG_SEQ_Prio_0);
+  /* USER CODE END OnTxPeriodicityChanged_1 */
+	HeartBeatPeriodicity = periodicity;
 
-	    	if (sts_ac_code[0]==0x0) {
-	    		// RFAC  Challenge
-	    		if (rfac_timer < (STS_BURN_IN_RFAC+3)) {
-	    			rfac_timer ++;
-	    		}
-	    		UTIL_SEQ_SetTask((1 << CFG_SEQ_Task_YunhornSTSEventRFAC), CFG_SEQ_Prio_0);
-	    	}
+  if (HeartBeatPeriodicity == 0)
+  {
+    /* Revert to application default periodicity */
+	  HeartBeatPeriodicity = 10*APP_TX_DUTYCYCLE;
+  }
 
+  /* Update timer periodicity */
 
-	    	UTIL_TIMER_Start(&YunhornSTSHeartBeatTimer);
-
-	    }
+	  UTIL_TIMER_Stop(&YunhornSTSHeartBeatTimer);
+	  UTIL_TIMER_SetPeriod(&YunhornSTSHeartBeatTimer, HeartBeatPeriodicity);
+	  UTIL_TIMER_Start(&YunhornSTSHeartBeatTimer);
 
+  /* USER CODE BEGIN OnTxPeriodicityChanged_2 */
+  APP_LOG(TS_OFF, VLEVEL_H,"**************** HeartBeatPeriodicity Changed to: %u (ms)\r\n", HeartBeatPeriodicity );
+  /* USER CODE END OnTxPeriodicityChanged_2 */
 }
-*/
 
 /**
   * @brief  Yunhorn STS  Sensor Sampling Periodicity/interval Change callback function
diff --git a/STM32CubeIDE/Release/STS_O7.bin b/STM32CubeIDE/Release/STS_O7.bin
index 59f7cfd..a4812ef 100644
Binary files a/STM32CubeIDE/Release/STS_O7.bin and b/STM32CubeIDE/Release/STS_O7.bin differ