diff --git a/NmraDcc.cpp b/NmraDcc.cpp
index 7523820..2dfb294 100644
--- a/NmraDcc.cpp
+++ b/NmraDcc.cpp
@@ -940,10 +940,18 @@ void processServiceModeOperation( DCC_MSG * pDccMsg )
 /////////////////////////////////////////////////////////////////////////
 void resetServiceModeTimer(uint8_t inServiceMode)
 {
+  if (notifyServiceMode && inServiceMode != DccProcState.inServiceMode)
+  {
+    notifyServiceMode(inServiceMode);
+  }
   // Set the Service Mode
   DccProcState.inServiceMode = inServiceMode ;
   
   DccProcState.LastServiceModeMillis = inServiceMode ? millis() : 0 ;
+  if (notifyServiceMode && inServiceMode != DccProcState.inServiceMode)
+  {
+    notifyServiceMode(inServiceMode);
+  }
 }
 
 /////////////////////////////////////////////////////////////////////////
@@ -1395,4 +1403,4 @@ uint8_t NmraDcc::process()
   }
 
   return 0 ;  
-};
\ No newline at end of file
+};
diff --git a/NmraDcc.h b/NmraDcc.h
index 991a5f1..42e12ae 100644
--- a/NmraDcc.h
+++ b/NmraDcc.h
@@ -671,6 +671,10 @@ extern void    notifyCVResetFactoryDefault(void) __attribute__ ((weak));
  *    None
  */
 extern void    notifyCVAck(void) __attribute__ ((weak));
+extern void    notifyServiceMode(bool) __attribute__ ((weak));
+
+// Deprecated, only for backward compatibility with version 1.4.2. Don't use in new designs
+extern void notifyDccAccState( uint16_t Addr, uint16_t BoardAddr, uint8_t OutputAddr, uint8_t State ) __attribute__ ((weak));
 
 // Deprecated, only for backward compatibility with version 1.4.2. Don't use in new designs
 extern void notifyDccAccState( uint16_t Addr, uint16_t BoardAddr, uint8_t OutputAddr, uint8_t State ) __attribute__ ((weak));