diff --git a/include/etl/error_handler.h b/include/etl/error_handler.h
index a5bdd2a0..065f2480 100644
--- a/include/etl/error_handler.h
+++ b/include/etl/error_handler.h
@@ -283,12 +283,12 @@ namespace etl
     #define ETL_ASSERT(b, e) {if(!(b)) {etl::error_handler::error((e));}}                  // If the condition fails, calls the error handler
     #define ETL_ALWAYS_ASSERT(e) {etl::error_handler::error((e));}                         // Calls the error handler
   #else
-    #if defined(NDEBUG)
-      #define ETL_ASSERT(b, e)                                                             // Does nothing.
-      #define ETL_ALWAYS_ASSERT(e)                                                         // Does nothing.
-    #else
+    #if defined(ETL_DEBUG)
       #define ETL_ASSERT(b, e) assert((b))                                                 // If the condition fails, asserts.
       #define ETL_ALWAYS_ASSERT(e) assert(false)                                           // Asserts.
+    #else
+      #define ETL_ASSERT(b, e)                                                             // Does nothing.
+      #define ETL_ALWAYS_ASSERT(e)                                                         // Does nothing.
     #endif
   #endif
 #endif
diff --git a/include/etl/fsm.h b/include/etl/fsm.h
index e079ee8a..30309404 100644
--- a/include/etl/fsm.h
+++ b/include/etl/fsm.h
@@ -191,7 +191,7 @@ namespace etl
 
   private:
 
-    virtual fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message) = 0;
+    virtual fsm_state_id_t process_event(const etl::imessage& message) = 0;
 
     virtual fsm_state_id_t on_enter_state() { return state_id; } // By default, do nothing.
     virtual void on_exit_state() {}  // By default, do nothing.
@@ -283,9 +283,9 @@ namespace etl
     //*******************************************
     /// Top level message handler for the FSM.
     //*******************************************
-    void receive(etl::imessage_router& source, const etl::imessage& message) ETL_OVERRIDE
+    void receive(const etl::imessage& message) ETL_OVERRIDE
     {
-        etl::fsm_state_id_t next_state_id = p_state->process_event(source, message);
+        etl::fsm_state_id_t next_state_id = p_state->process_event(message);
         ETL_ASSERT(next_state_id < number_of_states, ETL_ERROR(etl::fsm_state_id_exception));
 
         etl::ifsm_state* p_next_state = state_list[next_state_id];
@@ -427,30 +427,30 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T5&>(message)); break;
-        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T6&>(message)); break;
-        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T7&>(message)); break;
-        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T8&>(message)); break;
-        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T9&>(message)); break;
-        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T10&>(message)); break;
-        case T11::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T11&>(message)); break;
-        case T12::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T12&>(message)); break;
-        case T13::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T13&>(message)); break;
-        case T14::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T14&>(message)); break;
-        case T15::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T15&>(message)); break;
-        case T16::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T16&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T5&>(message)); break;
+        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T6&>(message)); break;
+        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T7&>(message)); break;
+        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T8&>(message)); break;
+        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T9&>(message)); break;
+        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T10&>(message)); break;
+        case T11::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T11&>(message)); break;
+        case T12::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T12&>(message)); break;
+        case T13::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T13&>(message)); break;
+        case T14::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T14&>(message)); break;
+        case T15::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T15&>(message)); break;
+        case T16::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T16&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -492,29 +492,29 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T5&>(message)); break;
-        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T6&>(message)); break;
-        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T7&>(message)); break;
-        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T8&>(message)); break;
-        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T9&>(message)); break;
-        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T10&>(message)); break;
-        case T11::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T11&>(message)); break;
-        case T12::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T12&>(message)); break;
-        case T13::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T13&>(message)); break;
-        case T14::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T14&>(message)); break;
-        case T15::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T15&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T5&>(message)); break;
+        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T6&>(message)); break;
+        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T7&>(message)); break;
+        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T8&>(message)); break;
+        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T9&>(message)); break;
+        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T10&>(message)); break;
+        case T11::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T11&>(message)); break;
+        case T12::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T12&>(message)); break;
+        case T13::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T13&>(message)); break;
+        case T14::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T14&>(message)); break;
+        case T15::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T15&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -556,28 +556,28 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T5&>(message)); break;
-        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T6&>(message)); break;
-        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T7&>(message)); break;
-        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T8&>(message)); break;
-        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T9&>(message)); break;
-        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T10&>(message)); break;
-        case T11::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T11&>(message)); break;
-        case T12::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T12&>(message)); break;
-        case T13::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T13&>(message)); break;
-        case T14::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T14&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T5&>(message)); break;
+        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T6&>(message)); break;
+        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T7&>(message)); break;
+        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T8&>(message)); break;
+        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T9&>(message)); break;
+        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T10&>(message)); break;
+        case T11::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T11&>(message)); break;
+        case T12::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T12&>(message)); break;
+        case T13::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T13&>(message)); break;
+        case T14::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T14&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -619,27 +619,27 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T5&>(message)); break;
-        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T6&>(message)); break;
-        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T7&>(message)); break;
-        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T8&>(message)); break;
-        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T9&>(message)); break;
-        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T10&>(message)); break;
-        case T11::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T11&>(message)); break;
-        case T12::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T12&>(message)); break;
-        case T13::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T13&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T5&>(message)); break;
+        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T6&>(message)); break;
+        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T7&>(message)); break;
+        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T8&>(message)); break;
+        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T9&>(message)); break;
+        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T10&>(message)); break;
+        case T11::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T11&>(message)); break;
+        case T12::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T12&>(message)); break;
+        case T13::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T13&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -680,26 +680,26 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T5&>(message)); break;
-        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T6&>(message)); break;
-        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T7&>(message)); break;
-        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T8&>(message)); break;
-        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T9&>(message)); break;
-        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T10&>(message)); break;
-        case T11::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T11&>(message)); break;
-        case T12::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T12&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T5&>(message)); break;
+        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T6&>(message)); break;
+        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T7&>(message)); break;
+        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T8&>(message)); break;
+        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T9&>(message)); break;
+        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T10&>(message)); break;
+        case T11::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T11&>(message)); break;
+        case T12::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T12&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -740,25 +740,25 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T5&>(message)); break;
-        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T6&>(message)); break;
-        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T7&>(message)); break;
-        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T8&>(message)); break;
-        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T9&>(message)); break;
-        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T10&>(message)); break;
-        case T11::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T11&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T5&>(message)); break;
+        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T6&>(message)); break;
+        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T7&>(message)); break;
+        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T8&>(message)); break;
+        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T9&>(message)); break;
+        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T10&>(message)); break;
+        case T11::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T11&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -799,24 +799,24 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T5&>(message)); break;
-        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T6&>(message)); break;
-        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T7&>(message)); break;
-        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T8&>(message)); break;
-        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T9&>(message)); break;
-        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T10&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T5&>(message)); break;
+        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T6&>(message)); break;
+        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T7&>(message)); break;
+        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T8&>(message)); break;
+        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T9&>(message)); break;
+        case T10::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T10&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -857,23 +857,23 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T5&>(message)); break;
-        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T6&>(message)); break;
-        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T7&>(message)); break;
-        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T8&>(message)); break;
-        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T9&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T5&>(message)); break;
+        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T6&>(message)); break;
+        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T7&>(message)); break;
+        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T8&>(message)); break;
+        case T9::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T9&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -913,22 +913,22 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T5&>(message)); break;
-        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T6&>(message)); break;
-        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T7&>(message)); break;
-        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T8&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T5&>(message)); break;
+        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T6&>(message)); break;
+        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T7&>(message)); break;
+        case T8::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T8&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -968,21 +968,21 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T5&>(message)); break;
-        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T6&>(message)); break;
-        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T7&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T5&>(message)); break;
+        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T6&>(message)); break;
+        case T7::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T7&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -1022,20 +1022,20 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T5&>(message)); break;
-        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T6&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T5&>(message)); break;
+        case T6::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T6&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -1075,19 +1075,19 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T5&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        case T5::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T5&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -1126,18 +1126,18 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T4&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        case T4::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T4&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -1176,17 +1176,17 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T3&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        case T3::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T3&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -1225,16 +1225,16 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T2&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        case T2::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T2&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -1273,15 +1273,15 @@ namespace etl
 
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
       etl::fsm_state_id_t new_state_id;
       etl::message_id_t event_id = message.get_message_id();
 
       switch (event_id)
       {
-        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T1&>(message)); break;
-        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message); break;
+        case T1::ID: new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T1&>(message)); break;
+        default: new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message); break;
       }
 
       return new_state_id;
@@ -1318,9 +1318,9 @@ namespace etl
     }
   private:
 
-    etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)
+    etl::fsm_state_id_t process_event(const etl::imessage& message)
     {
-      return static_cast<TDerived*>(this)->on_event_unknown(source, message);
+      return static_cast<TDerived*>(this)->on_event_unknown(message);
     }
   };
 }
diff --git a/include/etl/generators/fsm_generator.h b/include/etl/generators/fsm_generator.h
index 47450831..17048906 100644
--- a/include/etl/generators/fsm_generator.h
+++ b/include/etl/generators/fsm_generator.h
@@ -203,7 +203,7 @@ namespace etl
 
   private:
 
-    virtual fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message) = 0;
+    virtual fsm_state_id_t process_event(const etl::imessage& message) = 0;
 
     virtual fsm_state_id_t on_enter_state() { return state_id; } // By default, do nothing.
     virtual void on_exit_state() {}  // By default, do nothing.
@@ -295,9 +295,9 @@ namespace etl
     //*******************************************
     /// Top level message handler for the FSM.
     //*******************************************
-    void receive(etl::imessage_router& source, const etl::imessage& message) ETL_OVERRIDE
+    void receive(const etl::imessage& message) ETL_OVERRIDE
     {
-        etl::fsm_state_id_t next_state_id = p_state->process_event(source, message);
+        etl::fsm_state_id_t next_state_id = p_state->process_event(message);
         ETL_ASSERT(next_state_id < number_of_states, ETL_ERROR(etl::fsm_state_id_exception));
 
         etl::ifsm_state* p_next_state = state_list[next_state_id];
@@ -447,7 +447,7 @@ namespace etl
   cog.outl("")
   cog.outl("private:")
   cog.outl("")
-  cog.outl("  etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)")
+  cog.outl("  etl::fsm_state_id_t process_event(const etl::imessage& message)")
   cog.outl("  {")
   cog.outl("    etl::fsm_state_id_t new_state_id;")
   cog.outl("    etl::message_id_t event_id = message.get_message_id();")
@@ -456,10 +456,10 @@ namespace etl
   cog.outl("    {")
   for n in range(1, int(Handlers) + 1):
       cog.out("      case T%d::ID:" % n)
-      cog.out(" new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T%d&>(message));" % n)
+      cog.out(" new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T%d&>(message));" % n)
       cog.outl(" break;")
   cog.out("      default:")
-  cog.out(" new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message);")
+  cog.out(" new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message);")
   cog.outl(" break;")
   cog.outl("    }")
   cog.outl("")
@@ -524,7 +524,7 @@ namespace etl
       cog.outl("")
       cog.outl("private:")
       cog.outl("")
-      cog.outl("  etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)")
+      cog.outl("  etl::fsm_state_id_t process_event(const etl::imessage& message)")
       cog.outl("  {")
       cog.outl("    etl::fsm_state_id_t new_state_id;")
       cog.outl("    etl::message_id_t event_id = message.get_message_id();")
@@ -533,10 +533,10 @@ namespace etl
       cog.outl("    {")
       for n in range(1, n + 1):
           cog.out("      case T%d::ID:" % n)
-          cog.out(" new_state_id = static_cast<TDerived*>(this)->on_event(source, static_cast<const T%d&>(message));" % n)
+          cog.out(" new_state_id = static_cast<TDerived*>(this)->on_event(static_cast<const T%d&>(message));" % n)
           cog.outl(" break;")
       cog.out("      default:")
-      cog.out(" new_state_id = static_cast<TDerived*>(this)->on_event_unknown(source, message);")
+      cog.out(" new_state_id = static_cast<TDerived*>(this)->on_event_unknown(message);")
       cog.outl(" break;")
       cog.outl("    }")
       cog.outl("")
@@ -583,9 +583,9 @@ namespace etl
   cog.outl("  }")
   cog.outl("private:")
   cog.outl("")
-  cog.outl("  etl::fsm_state_id_t process_event(etl::imessage_router& source, const etl::imessage& message)")
+  cog.outl("  etl::fsm_state_id_t process_event(const etl::imessage& message)")
   cog.outl("  {")
-  cog.outl("    return static_cast<TDerived*>(this)->on_event_unknown(source, message);")
+  cog.outl("    return static_cast<TDerived*>(this)->on_event_unknown(message);")
   cog.outl("  }")
   cog.outl("};")
   ]]]*/
diff --git a/include/etl/generators/message_router_generator.h b/include/etl/generators/message_router_generator.h
index fefa7a5c..6a6d70e0 100644
--- a/include/etl/generators/message_router_generator.h
+++ b/include/etl/generators/message_router_generator.h
@@ -124,60 +124,36 @@ namespace etl
   public:
 
     virtual ~imessage_router() {}
-    virtual void receive(etl::imessage_router& source, const etl::imessage& message) = 0;
+    virtual void receive(const etl::imessage& message) = 0;
     virtual bool accepts(etl::message_id_t id) const = 0;
     virtual bool is_null_router() const = 0;
     virtual bool is_producer() const = 0;
     virtual bool is_consumer() const = 0;
 
     //********************************************
-    virtual void receive(etl::imessage_router& source, etl::message_router_id_t destination_router_id, const etl::imessage& message)
+    virtual void receive(etl::message_router_id_t destination_router_id, const etl::imessage& message)
     {
       if ((destination_router_id == get_message_router_id()) || (destination_router_id == imessage_router::ALL_MESSAGE_ROUTERS))
       {
-        receive(source, message);
+        receive(message);
       }
     }
 
     //********************************************
-    void receive(etl::message_router_id_t destination_router_id, const etl::imessage& message)
+    virtual void receive(etl::shared_message shared_msg)
     {
-      receive(etl::get_null_message_router(), destination_router_id, message);
+      receive(shared_msg.get_message());
     }
 
     //********************************************
-    void receive(const etl::imessage& message)
-    {
-      receive(etl::get_null_message_router(), message);
-    }
-
-    //********************************************
-    virtual void receive(etl::imessage_router& source, etl::shared_message shared_msg)
-    {
-      receive(source, shared_msg.get_message());
-    }
-
-    //********************************************
-    virtual void receive(etl::imessage_router& source, etl::message_router_id_t destination_router_id, etl::shared_message shared_msg)
+    virtual void receive(etl::message_router_id_t destination_router_id, etl::shared_message shared_msg)
     {
       if ((destination_router_id == get_message_router_id()) || (destination_router_id == imessage_router::ALL_MESSAGE_ROUTERS))
       {
-        receive(source, shared_msg);
+        receive(shared_msg);
       }
     }
 
-    //********************************************
-    void receive(etl::message_router_id_t destination_router_id, etl::shared_message shared_msg)
-    {
-      receive(etl::get_null_message_router(), destination_router_id, shared_msg);
-    }
-
-    //********************************************
-    void receive(etl::shared_message shared_msg)
-    {
-      receive(etl::get_null_message_router(), shared_msg);
-    }
-
     //********************************************
     bool accepts(const etl::imessage& msg) const
     {
@@ -234,7 +210,7 @@ namespace etl
     //********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router&, const etl::imessage&) ETL_OVERRIDE
+    void receive(const etl::imessage&) ETL_OVERRIDE
     {
     }
 
@@ -294,7 +270,7 @@ namespace etl
     //********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router&, const etl::imessage&) ETL_OVERRIDE
+    void receive(const etl::imessage&) ETL_OVERRIDE
     {
     }
 
@@ -324,9 +300,9 @@ namespace etl
       return false;
     }
   };
+
   //***************************************************************************
   /// Send a message to a router.
-  /// Sets the 'sender' to etl::null_message_router type.
   //***************************************************************************
   inline static void send_message(etl::imessage_router& destination,
                                   const etl::imessage&  message)
@@ -334,16 +310,6 @@ namespace etl
     destination.receive(message);
   }
 
-  //***************************************************************************
-  /// Send a message to a router.
-  //***************************************************************************
-  inline static void send_message(etl::imessage_router& source,
-                                  etl::imessage_router& destination,
-                                  const etl::imessage&  message)
-  {
-    destination.receive(source, message);
-  }
-
   /*[[[cog
       import cog
       ################################################
@@ -388,7 +354,7 @@ namespace etl
       cog.outl("  //**********************************************")
       cog.outl("  using etl::imessage_router::receive;")
       cog.outl("")
-      cog.outl("  void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE")
+      cog.outl("  void receive(const etl::imessage& msg) ETL_OVERRIDE")
       cog.outl("  {")
       cog.outl("    const etl::message_id_t id = msg.get_message_id();")
       cog.outl("")
@@ -396,17 +362,17 @@ namespace etl
       cog.outl("    {")
       for n in range(1, int(Handlers) + 1):
           cog.out("      case T%d::ID:" % n)
-          cog.out(" static_cast<TDerived*>(this)->on_receive(source, static_cast<const T%d&>(msg));" % n)
+          cog.out(" static_cast<TDerived*>(this)->on_receive(static_cast<const T%d&>(msg));" % n)
           cog.outl(" break;")
       cog.outl("      default:")
       cog.outl("      {")
       cog.outl("         if (has_successor())")
       cog.outl("         {")
-      cog.outl("           get_successor().receive(source, msg);")
+      cog.outl("           get_successor().receive(msg);")
       cog.outl("         }")
       cog.outl("         else")
       cog.outl("         {")
-      cog.outl("           static_cast<TDerived*>(this)->on_receive_unknown(source, msg);")
+      cog.outl("           static_cast<TDerived*>(this)->on_receive_unknown(msg);")
       cog.outl("         }")
       cog.outl("         break;")
       cog.outl("      }")
@@ -508,7 +474,7 @@ namespace etl
           cog.outl("  //**********************************************")
           cog.outl("  using etl::imessage_router::receive;")
           cog.outl("")
-          cog.outl("  void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE")
+          cog.outl("  void receive(const etl::imessage& msg) ETL_OVERRIDE")
           cog.outl("  {")
           cog.outl("    const size_t id = msg.get_message_id();")
           cog.outl("")
@@ -516,17 +482,17 @@ namespace etl
           cog.outl("    {")
           for t in range(1, n + 1):
               cog.out("      case T%d::ID:" % t)
-              cog.out(" static_cast<TDerived*>(this)->on_receive(source, static_cast<const T%d&>(msg));" % t)
+              cog.out(" static_cast<TDerived*>(this)->on_receive(static_cast<const T%d&>(msg));" % t)
               cog.outl(" break;")
           cog.outl("      default:")
           cog.outl("      {")
           cog.outl("         if (has_successor())")
           cog.outl("         {")
-          cog.outl("           get_successor().receive(source, msg);")
+          cog.outl("           get_successor().receive(msg);")
           cog.outl("         }")
           cog.outl("         else")
           cog.outl("         {")
-          cog.outl("           static_cast<TDerived*>(this)->on_receive_unknown(source, msg);")
+          cog.outl("           static_cast<TDerived*>(this)->on_receive_unknown(msg);")
           cog.outl("         }")
           cog.outl("         break;")
           cog.outl("      }")
diff --git a/include/etl/message_bus.h b/include/etl/message_bus.h
index 6897645f..af05bb5e 100644
--- a/include/etl/message_bus.h
+++ b/include/etl/message_bus.h
@@ -148,22 +148,19 @@ namespace etl
     }
 
     //*******************************************
-    virtual void receive(etl::imessage_router& source,
-                         const etl::imessage& message) ETL_OVERRIDE
+    virtual void receive(const etl::imessage& message) ETL_OVERRIDE
     {
-      receive(source, etl::imessage_router::ALL_MESSAGE_ROUTERS, message);
+      receive(etl::imessage_router::ALL_MESSAGE_ROUTERS, message);
     }
 
     //*******************************************
-    virtual void receive(etl::imessage_router& source,
-                         etl::shared_message   shared_msg) ETL_OVERRIDE
+    virtual void receive(etl::shared_message   shared_msg) ETL_OVERRIDE
     {
-      receive(source, etl::imessage_router::ALL_MESSAGE_ROUTERS, shared_msg);
+      receive(etl::imessage_router::ALL_MESSAGE_ROUTERS, shared_msg);
     }
 
     //********************************************
-    virtual void receive(etl::imessage_router&    source,
-                         etl::message_router_id_t destination_router_id, 
+    virtual void receive(etl::message_router_id_t destination_router_id, 
                          etl::shared_message      shared_msg) ETL_OVERRIDE
     {
       switch (destination_router_id)
@@ -181,7 +178,7 @@ namespace etl
 
             if (router.accepts(shared_msg.get_message().get_message_id()))
             {
-              router.receive(source, shared_msg);
+              router.receive(shared_msg);
             }
 
             ++irouter;
@@ -207,7 +204,7 @@ namespace etl
           {
             if ((*(range.first))->accepts(shared_msg.get_message().get_message_id()))
             {
-              (*(range.first))->receive(source, shared_msg);
+              (*(range.first))->receive(shared_msg);
             }
 
             ++range.first;
@@ -223,7 +220,7 @@ namespace etl
           while (irouter != router_list.end())
           {
             // So pass it on.
-            (*irouter)->receive(source, destination_router_id, shared_msg);
+            (*irouter)->receive(destination_router_id, shared_msg);
 
             ++irouter;
           }
@@ -234,8 +231,7 @@ namespace etl
     }
 
     //*******************************************
-    virtual void receive(etl::imessage_router&    source,
-                         etl::message_router_id_t destination_router_id,
+    virtual void receive(etl::message_router_id_t destination_router_id,
                          const etl::imessage&     message) ETL_OVERRIDE
     {
       switch (destination_router_id)
@@ -253,7 +249,7 @@ namespace etl
 
             if (router.accepts(message.get_message_id()))
             {
-              router.receive(source, message);
+              router.receive(message);
             }
 
             ++irouter;
@@ -279,7 +275,7 @@ namespace etl
           {
             if ((*(range.first))->accepts(message.get_message_id()))
             {
-              (*(range.first))->receive(source, message);
+              (*(range.first))->receive(message);
             }
 
             ++range.first;
@@ -288,14 +284,14 @@ namespace etl
           // Do any message buses.
           // These are always at the end of the list.
           irouter = etl::lower_bound(router_list.begin(),
-                                        router_list.end(),
-                                        etl::imessage_bus::MESSAGE_BUS,
-                                        compare_router_id());
+                                     router_list.end(),
+                                     etl::imessage_bus::MESSAGE_BUS,
+                                     compare_router_id());
 
           while (irouter != router_list.end())
           {
             // So pass it on.
-            (*irouter)->receive(source, destination_router_id, message);
+            (*irouter)->receive(destination_router_id, message);
 
             ++irouter;
           }
@@ -425,7 +421,7 @@ namespace etl
                                   etl::imessage_bus&    bus,
                                   const etl::imessage&  message)
   {
-    bus.receive(source, message);
+    bus.receive(message);
   }
 
   //***************************************************************************
@@ -436,7 +432,7 @@ namespace etl
                                   etl::message_router_id_t id,
                                   const etl::imessage&     message)
   {
-    bus.receive(source, id, message);
+    bus.receive(id, message);
   }
 }
 
diff --git a/include/etl/message_router.h b/include/etl/message_router.h
index b3888499..83ed4e39 100644
--- a/include/etl/message_router.h
+++ b/include/etl/message_router.h
@@ -112,60 +112,36 @@ namespace etl
   public:
 
     virtual ~imessage_router() {}
-    virtual void receive(etl::imessage_router& source, const etl::imessage& message) = 0;
+    virtual void receive(const etl::imessage& message) = 0;
     virtual bool accepts(etl::message_id_t id) const = 0;
     virtual bool is_null_router() const = 0;
     virtual bool is_producer() const = 0;
     virtual bool is_consumer() const = 0;
 
     //********************************************
-    virtual void receive(etl::imessage_router& source, etl::message_router_id_t destination_router_id, const etl::imessage& message)
+    virtual void receive(etl::message_router_id_t destination_router_id, const etl::imessage& message)
     {
       if ((destination_router_id == get_message_router_id()) || (destination_router_id == imessage_router::ALL_MESSAGE_ROUTERS))
       {
-        receive(source, message);
+        receive(message);
       }
     }
 
     //********************************************
-    void receive(etl::message_router_id_t destination_router_id, const etl::imessage& message)
+    virtual void receive(etl::shared_message shared_msg)
     {
-      receive(etl::get_null_message_router(), destination_router_id, message);
+      receive(shared_msg.get_message());
     }
 
     //********************************************
-    void receive(const etl::imessage& message)
-    {
-      receive(etl::get_null_message_router(), message);
-    }
-
-    //********************************************
-    virtual void receive(etl::imessage_router& source, etl::shared_message shared_msg)
-    {
-      receive(source, shared_msg.get_message());
-    }
-
-    //********************************************
-    virtual void receive(etl::imessage_router& source, etl::message_router_id_t destination_router_id, etl::shared_message shared_msg)
+    virtual void receive(etl::message_router_id_t destination_router_id, etl::shared_message shared_msg)
     {
       if ((destination_router_id == get_message_router_id()) || (destination_router_id == imessage_router::ALL_MESSAGE_ROUTERS))
       {
-        receive(source, shared_msg);
+        receive(shared_msg);
       }
     }
 
-    //********************************************
-    void receive(etl::message_router_id_t destination_router_id, etl::shared_message shared_msg)
-    {
-      receive(etl::get_null_message_router(), destination_router_id, shared_msg);
-    }
-
-    //********************************************
-    void receive(etl::shared_message shared_msg)
-    {
-      receive(etl::get_null_message_router(), shared_msg);
-    }
-
     //********************************************
     bool accepts(const etl::imessage& msg) const
     {
@@ -222,7 +198,7 @@ namespace etl
     //********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router&, const etl::imessage&) ETL_OVERRIDE
+    void receive(const etl::imessage&) ETL_OVERRIDE
     {
     }
 
@@ -282,7 +258,7 @@ namespace etl
     //********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router&, const etl::imessage&) ETL_OVERRIDE
+    void receive(const etl::imessage&) ETL_OVERRIDE
     {
     }
 
@@ -312,9 +288,9 @@ namespace etl
       return false;
     }
   };
+
   //***************************************************************************
   /// Send a message to a router.
-  /// Sets the 'sender' to etl::null_message_router type.
   //***************************************************************************
   inline static void send_message(etl::imessage_router& destination,
                                   const etl::imessage&  message)
@@ -322,16 +298,6 @@ namespace etl
     destination.receive(message);
   }
 
-  //***************************************************************************
-  /// Send a message to a router.
-  //***************************************************************************
-  inline static void send_message(etl::imessage_router& source,
-                                  etl::imessage_router& destination,
-                                  const etl::imessage&  message)
-  {
-    destination.receive(source, message);
-  }
-
   //***************************************************************************
   // The definition for all 16 message types.
   //***************************************************************************
@@ -363,37 +329,37 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const etl::message_id_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
-        case T5::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T5&>(msg)); break;
-        case T6::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T6&>(msg)); break;
-        case T7::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T7&>(msg)); break;
-        case T8::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T8&>(msg)); break;
-        case T9::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T9&>(msg)); break;
-        case T10::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T10&>(msg)); break;
-        case T11::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T11&>(msg)); break;
-        case T12::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T12&>(msg)); break;
-        case T13::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T13&>(msg)); break;
-        case T14::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T14&>(msg)); break;
-        case T15::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T15&>(msg)); break;
-        case T16::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T16&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
+        case T5::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T5&>(msg)); break;
+        case T6::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T6&>(msg)); break;
+        case T7::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T7&>(msg)); break;
+        case T8::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T8&>(msg)); break;
+        case T9::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T9&>(msg)); break;
+        case T10::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T10&>(msg)); break;
+        case T11::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T11&>(msg)); break;
+        case T12::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T12&>(msg)); break;
+        case T13::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T13&>(msg)); break;
+        case T14::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T14&>(msg)); break;
+        case T15::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T15&>(msg)); break;
+        case T16::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T16&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -466,36 +432,36 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
-        case T5::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T5&>(msg)); break;
-        case T6::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T6&>(msg)); break;
-        case T7::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T7&>(msg)); break;
-        case T8::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T8&>(msg)); break;
-        case T9::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T9&>(msg)); break;
-        case T10::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T10&>(msg)); break;
-        case T11::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T11&>(msg)); break;
-        case T12::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T12&>(msg)); break;
-        case T13::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T13&>(msg)); break;
-        case T14::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T14&>(msg)); break;
-        case T15::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T15&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
+        case T5::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T5&>(msg)); break;
+        case T6::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T6&>(msg)); break;
+        case T7::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T7&>(msg)); break;
+        case T8::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T8&>(msg)); break;
+        case T9::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T9&>(msg)); break;
+        case T10::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T10&>(msg)); break;
+        case T11::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T11&>(msg)); break;
+        case T12::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T12&>(msg)); break;
+        case T13::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T13&>(msg)); break;
+        case T14::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T14&>(msg)); break;
+        case T15::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T15&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -568,35 +534,35 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
-        case T5::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T5&>(msg)); break;
-        case T6::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T6&>(msg)); break;
-        case T7::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T7&>(msg)); break;
-        case T8::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T8&>(msg)); break;
-        case T9::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T9&>(msg)); break;
-        case T10::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T10&>(msg)); break;
-        case T11::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T11&>(msg)); break;
-        case T12::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T12&>(msg)); break;
-        case T13::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T13&>(msg)); break;
-        case T14::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T14&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
+        case T5::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T5&>(msg)); break;
+        case T6::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T6&>(msg)); break;
+        case T7::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T7&>(msg)); break;
+        case T8::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T8&>(msg)); break;
+        case T9::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T9&>(msg)); break;
+        case T10::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T10&>(msg)); break;
+        case T11::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T11&>(msg)); break;
+        case T12::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T12&>(msg)); break;
+        case T13::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T13&>(msg)); break;
+        case T14::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T14&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -669,34 +635,34 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
-        case T5::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T5&>(msg)); break;
-        case T6::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T6&>(msg)); break;
-        case T7::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T7&>(msg)); break;
-        case T8::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T8&>(msg)); break;
-        case T9::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T9&>(msg)); break;
-        case T10::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T10&>(msg)); break;
-        case T11::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T11&>(msg)); break;
-        case T12::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T12&>(msg)); break;
-        case T13::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T13&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
+        case T5::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T5&>(msg)); break;
+        case T6::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T6&>(msg)); break;
+        case T7::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T7&>(msg)); break;
+        case T8::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T8&>(msg)); break;
+        case T9::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T9&>(msg)); break;
+        case T10::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T10&>(msg)); break;
+        case T11::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T11&>(msg)); break;
+        case T12::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T12&>(msg)); break;
+        case T13::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T13&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -768,33 +734,33 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
-        case T5::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T5&>(msg)); break;
-        case T6::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T6&>(msg)); break;
-        case T7::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T7&>(msg)); break;
-        case T8::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T8&>(msg)); break;
-        case T9::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T9&>(msg)); break;
-        case T10::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T10&>(msg)); break;
-        case T11::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T11&>(msg)); break;
-        case T12::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T12&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
+        case T5::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T5&>(msg)); break;
+        case T6::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T6&>(msg)); break;
+        case T7::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T7&>(msg)); break;
+        case T8::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T8&>(msg)); break;
+        case T9::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T9&>(msg)); break;
+        case T10::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T10&>(msg)); break;
+        case T11::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T11&>(msg)); break;
+        case T12::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T12&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -866,32 +832,32 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
-        case T5::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T5&>(msg)); break;
-        case T6::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T6&>(msg)); break;
-        case T7::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T7&>(msg)); break;
-        case T8::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T8&>(msg)); break;
-        case T9::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T9&>(msg)); break;
-        case T10::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T10&>(msg)); break;
-        case T11::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T11&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
+        case T5::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T5&>(msg)); break;
+        case T6::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T6&>(msg)); break;
+        case T7::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T7&>(msg)); break;
+        case T8::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T8&>(msg)); break;
+        case T9::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T9&>(msg)); break;
+        case T10::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T10&>(msg)); break;
+        case T11::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T11&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -963,31 +929,31 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
-        case T5::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T5&>(msg)); break;
-        case T6::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T6&>(msg)); break;
-        case T7::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T7&>(msg)); break;
-        case T8::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T8&>(msg)); break;
-        case T9::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T9&>(msg)); break;
-        case T10::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T10&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
+        case T5::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T5&>(msg)); break;
+        case T6::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T6&>(msg)); break;
+        case T7::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T7&>(msg)); break;
+        case T8::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T8&>(msg)); break;
+        case T9::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T9&>(msg)); break;
+        case T10::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T10&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -1059,30 +1025,30 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
-        case T5::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T5&>(msg)); break;
-        case T6::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T6&>(msg)); break;
-        case T7::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T7&>(msg)); break;
-        case T8::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T8&>(msg)); break;
-        case T9::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T9&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
+        case T5::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T5&>(msg)); break;
+        case T6::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T6&>(msg)); break;
+        case T7::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T7&>(msg)); break;
+        case T8::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T8&>(msg)); break;
+        case T9::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T9&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -1153,29 +1119,29 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
-        case T5::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T5&>(msg)); break;
-        case T6::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T6&>(msg)); break;
-        case T7::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T7&>(msg)); break;
-        case T8::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T8&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
+        case T5::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T5&>(msg)); break;
+        case T6::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T6&>(msg)); break;
+        case T7::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T7&>(msg)); break;
+        case T8::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T8&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -1246,28 +1212,28 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
-        case T5::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T5&>(msg)); break;
-        case T6::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T6&>(msg)); break;
-        case T7::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T7&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
+        case T5::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T5&>(msg)); break;
+        case T6::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T6&>(msg)); break;
+        case T7::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T7&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -1337,27 +1303,27 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
-        case T5::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T5&>(msg)); break;
-        case T6::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T6&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
+        case T5::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T5&>(msg)); break;
+        case T6::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T6&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -1427,26 +1393,26 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
-        case T5::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T5&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
+        case T5::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T5&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -1515,25 +1481,25 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
-        case T4::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T4&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
+        case T4::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T4&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -1602,24 +1568,24 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
-        case T3::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T3&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
+        case T3::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T3&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -1688,23 +1654,23 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
-        case T2::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T2&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
+        case T2::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T2&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
@@ -1773,22 +1739,22 @@ namespace etl
     //**********************************************
     using etl::imessage_router::receive;
 
-    void receive(etl::imessage_router& source, const etl::imessage& msg) ETL_OVERRIDE
+    void receive(const etl::imessage& msg) ETL_OVERRIDE
     {
       const size_t id = msg.get_message_id();
 
       switch (id)
       {
-        case T1::ID: static_cast<TDerived*>(this)->on_receive(source, static_cast<const T1&>(msg)); break;
+        case T1::ID: static_cast<TDerived*>(this)->on_receive(static_cast<const T1&>(msg)); break;
         default:
         {
            if (has_successor())
            {
-             get_successor().receive(source, msg);
+             get_successor().receive(msg);
            }
            else
            {
-             static_cast<TDerived*>(this)->on_receive_unknown(source, msg);
+             static_cast<TDerived*>(this)->on_receive_unknown(msg);
            }
            break;
         }
diff --git a/include/etl/message_timer.h b/include/etl/message_timer.h
index ca5a9204..3b69a713 100644
--- a/include/etl/message_timer.h
+++ b/include/etl/message_timer.h
@@ -473,8 +473,7 @@ namespace etl
 
               if (timer.p_router != ETL_NULLPTR)
               {
-                static etl::null_message_router nmr;
-                timer.p_router->receive(nmr, timer.destination_router_id, *(timer.p_message));
+                timer.p_router->receive(timer.destination_router_id, *(timer.p_message));
               }
 
               has_active = !active_list.empty();
diff --git a/include/etl/version.h b/include/etl/version.h
index c3050e6d..d4712e24 100644
--- a/include/etl/version.h
+++ b/include/etl/version.h
@@ -37,9 +37,9 @@ SOFTWARE.
 /// Definitions of the ETL version
 ///\ingroup utilities
 
-#define ETL_VERSION_MAJOR 19
-#define ETL_VERSION_MINOR  5
-#define ETL_VERSION_PATCH  3
+#define ETL_VERSION_MAJOR 20
+#define ETL_VERSION_MINOR  0
+#define ETL_VERSION_PATCH  0
 #define ETL_VERSION       ETL_STRINGIFY(ETL_VERSION_MAJOR) "." ETL_STRINGIFY(ETL_VERSION_MINOR) "." ETL_STRINGIFY(ETL_VERSION_PATCH)
 #define ETL_VERSION_W     ETL_STRINGIFY(ETL_VERSION_MAJOR) L"." ETL_STRINGIFY(ETL_VERSION_MINOR) L"." ETL_STRINGIFY(ETL_VERSION_PATCH)
 #define ETL_VERSION_U16   ETL_STRINGIFY(ETL_VERSION_MAJOR) u"." ETL_STRINGIFY(ETL_VERSION_MINOR) u"." ETL_STRINGIFY(ETL_VERSION_PATCH)
diff --git a/library.json b/library.json
index 7220da59..b493356a 100644
--- a/library.json
+++ b/library.json
@@ -1,6 +1,6 @@
 {
   "name": "ETL Embedded Template Library",
-  "version": "19.5.3",
+  "version": "20.0.0",
   "author s": {
     "name": "John Wellbelove",
     "email": "john.wellbelove@etlcpp.com"
diff --git a/library.properties b/library.properties
index 176e7491..2b145669 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=Embedded Template Library ETL
-version=19.5.3
+version=20.0.0
 author= John Wellbelove <john.wellbelove@etlcpp.com>
 maintainer=John Wellbelove <john.wellbelove@etlcpp.com>
 license=MIT
diff --git a/support/Release notes.txt b/support/Release notes.txt
index d744c11b..fca3d8c9 100644
--- a/support/Release notes.txt	
+++ b/support/Release notes.txt	
@@ -1,3 +1,8 @@
+===============================================================================
+20.0.0
+Removed source 'etl::imessage_router&' parameter from the message framework 'receive'
+and 'on_receive' member functions.
+
 ===============================================================================
 19.5.3
 Added move constructor and move assignment operator to etl::shared_message.
diff --git a/test/test_fsm.cpp b/test/test_fsm.cpp
index 49b7d369..3127e51b 100644
--- a/test/test_fsm.cpp
+++ b/test/test_fsm.cpp
@@ -207,21 +207,21 @@ namespace
   public:
 
     //***********************************
-    etl::fsm_state_id_t on_event(etl::imessage_router&, const Start&)
+    etl::fsm_state_id_t on_event(const Start&)
     {
       ++get_fsm_context().startCount;
       return StateId::RUNNING;
     }
 
     //***********************************
-    etl::fsm_state_id_t on_event(etl::imessage_router&, const Recursive&)
+    etl::fsm_state_id_t on_event(const Recursive&)
     {
       get_fsm_context().queue_recursive_message(Start());
       return StateId::IDLE;
     }
 
     //***********************************
-    etl::fsm_state_id_t on_event_unknown(etl::imessage_router&, const etl::imessage&)
+    etl::fsm_state_id_t on_event_unknown(const etl::imessage&)
     {
       ++get_fsm_context().unknownCount;
       return STATE_ID;
@@ -243,7 +243,7 @@ namespace
   public:
 
     //***********************************
-    etl::fsm_state_id_t on_event(etl::imessage_router&, const Stop& event)
+    etl::fsm_state_id_t on_event(const Stop& event)
     {
       ++get_fsm_context().stopCount;
 
@@ -258,7 +258,7 @@ namespace
     }
 
     //***********************************
-    etl::fsm_state_id_t on_event(etl::imessage_router&, const SetSpeed& event)
+    etl::fsm_state_id_t on_event(const SetSpeed& event)
     {
       ++get_fsm_context().setSpeedCount;
       get_fsm_context().SetSpeedValue(event.speed);
@@ -266,7 +266,7 @@ namespace
     }
 
     //***********************************
-    etl::fsm_state_id_t on_event_unknown(etl::imessage_router&, const etl::imessage&)
+    etl::fsm_state_id_t on_event_unknown(const etl::imessage&)
     {
       ++get_fsm_context().unknownCount;
       return STATE_ID;
@@ -289,14 +289,14 @@ namespace
   public:
 
     //***********************************
-    etl::fsm_state_id_t on_event(etl::imessage_router&, const Stopped&)
+    etl::fsm_state_id_t on_event(const Stopped&)
     {
       ++get_fsm_context().stoppedCount;
       return StateId::IDLE;
     }
 
     //***********************************
-    etl::fsm_state_id_t on_event_unknown(etl::imessage_router&, const etl::imessage&)
+    etl::fsm_state_id_t on_event_unknown(const etl::imessage&)
     {
       ++get_fsm_context().unknownCount;
       return STATE_ID;
@@ -311,7 +311,7 @@ namespace
   public:
 
     //***********************************
-    etl::fsm_state_id_t on_event_unknown(etl::imessage_router&, const etl::imessage&)
+    etl::fsm_state_id_t on_event_unknown(const etl::imessage&)
     {
       ++get_fsm_context().unknownCount;
       return STATE_ID;
@@ -365,9 +365,9 @@ namespace
       CHECK_EQUAL(0, motorControl.unknownCount);
 
       // Send unhandled events.
-      motorControl.receive(nmr, Stop());
-      motorControl.receive(nmr, Stopped());
-      motorControl.receive(nmr, SetSpeed(10));
+      motorControl.receive(Stop());
+      motorControl.receive(Stopped());
+      motorControl.receive(SetSpeed(10));
 
       CHECK_EQUAL(StateId::IDLE, motorControl.get_state_id());
       CHECK_EQUAL(StateId::IDLE, motorControl.get_state().get_state_id());
@@ -381,7 +381,7 @@ namespace
       CHECK_EQUAL(3, motorControl.unknownCount);
 
       // Send Start event.
-      motorControl.receive(nmr, Start());
+      motorControl.receive(Start());
 
       // Now in Running state.
 
@@ -397,8 +397,8 @@ namespace
       CHECK_EQUAL(3, motorControl.unknownCount);
 
       // Send unhandled events.
-      motorControl.receive(nmr, Start());
-      motorControl.receive(nmr, Stopped());
+      motorControl.receive(Start());
+      motorControl.receive(Stopped());
 
       CHECK_EQUAL(StateId::RUNNING, int(motorControl.get_state_id()));
       CHECK_EQUAL(StateId::RUNNING, int(motorControl.get_state().get_state_id()));
@@ -412,7 +412,7 @@ namespace
       CHECK_EQUAL(5, motorControl.unknownCount);
 
       // Send SetSpeed event.
-      motorControl.receive(nmr, SetSpeed(100));
+      motorControl.receive(SetSpeed(100));
 
       // Still in Running state.
 
@@ -428,7 +428,7 @@ namespace
       CHECK_EQUAL(5, motorControl.unknownCount);
 
       // Send Stop event.
-      motorControl.receive(nmr, Stop());
+      motorControl.receive(Stop());
 
       // Now in WindingDown state.
 
@@ -444,9 +444,9 @@ namespace
       CHECK_EQUAL(5, motorControl.unknownCount);
 
       // Send unhandled events.
-      motorControl.receive(nmr, Start());
-      motorControl.receive(nmr, Stop());
-      motorControl.receive(nmr, SetSpeed(100));
+      motorControl.receive(Start());
+      motorControl.receive(Stop());
+      motorControl.receive(SetSpeed(100));
 
       CHECK_EQUAL(StateId::WINDING_DOWN, int(motorControl.get_state_id()));
       CHECK_EQUAL(StateId::WINDING_DOWN, int(motorControl.get_state().get_state_id()));
@@ -460,7 +460,7 @@ namespace
       CHECK_EQUAL(8, motorControl.unknownCount);
 
       // Send Stopped event.
-      motorControl.receive(nmr, Stopped());
+      motorControl.receive(Stopped());
 
       // Now in Locked state via Idle state.
       CHECK_EQUAL(StateId::LOCKED, int(motorControl.get_state_id()));
@@ -493,7 +493,7 @@ namespace
       // Now in Idle state.
 
       // Send Start event.
-      motorControl.receive(nmr, Start());
+      motorControl.receive(Start());
 
       // Now in Running state.
 
@@ -509,7 +509,7 @@ namespace
       CHECK_EQUAL(0, motorControl.unknownCount);
 
       // Send emergency Stop event.
-      motorControl.receive(nmr, Stop(true));
+      motorControl.receive(Stop(true));
 
       // Now in Locked state via Idle state.
       CHECK_EQUAL(StateId::LOCKED, int(motorControl.get_state_id()));
@@ -540,12 +540,12 @@ namespace
 
       // Now in Idle state.
       // Send Start event.
-      motorControl.receive(nmr, Recursive());
+      motorControl.receive(Recursive());
 
       CHECK_EQUAL(1U, motorControl.messageQueue.size());
 
       // Send the queued message.
-      motorControl.receive(nmr, motorControl.messageQueue.front().get());
+      motorControl.receive(motorControl.messageQueue.front().get());
       motorControl.messageQueue.pop();
 
       // Now in Running state.
diff --git a/test/test_message_bus.cpp b/test/test_message_bus.cpp
index 91bf7f37..d158ecf4 100644
--- a/test/test_message_bus.cpp
+++ b/test/test_message_bus.cpp
@@ -60,37 +60,57 @@ namespace
 
   struct Message1 : public etl::message<MESSAGE1>
   {
+    Message1(etl::imessage_router& callback_)
+      : callback(callback_)
+    {
+    }
+
+    etl::imessage_router& callback;
   };
 
   struct Message2 : public etl::message<MESSAGE2>
   {
+    Message2(etl::imessage_router& callback_)
+      : callback(callback_)
+    {
+    }
+
+    etl::imessage_router& callback;
   };
 
   struct Message3 : public etl::message<MESSAGE3>
   {
+    Message3(etl::imessage_router& callback_)
+      : callback(callback_)
+    {
+    }
+
+    etl::imessage_router& callback;
     int value[10];
   };
 
   struct Message4 : public etl::message<MESSAGE4>
   {
+    Message4(etl::imessage_router& callback_)
+      : callback(callback_)
+    {
+    }
+
+    etl::imessage_router& callback;
   };
 
-  struct Message5 : public etl::message<MESSAGE5>
+  struct Response : public etl::message<MESSAGE5>
   {
   };
 
-  Message1 message1;
-  Message2 message2;
-  Message3 message3;
-  Message4 message4;
-  Message5 message5;
+  Response response;
 
   int call_order;
 
   //***************************************************************************
   // Router that handles messages 1, 2, 3, 4, 5.
   //***************************************************************************
-  class RouterA : public etl::message_router<RouterA, Message1, Message2, Message3, Message4, Message5>
+  class RouterA : public etl::message_router<RouterA, Message1, Message2, Message3, Message4, Response>
   {
   public:
 
@@ -106,38 +126,38 @@ namespace
 
     }
 
-    void on_receive(etl::imessage_router& sender, const Message1&)
+    void on_receive(const Message1& msg)
     {
       ++message1_count;
-      etl::send_message(sender, message5);
+      etl::send_message(msg.callback, response);
 
       order = call_order++;
     }
 
-    void on_receive(etl::imessage_router& sender, const Message2&)
+    void on_receive(const Message2& msg)
     {
       ++message2_count;
-      etl::send_message(sender, message5);
+      etl::send_message(msg.callback, response);
     }
 
-    void on_receive(etl::imessage_router& sender, const Message3&)
+    void on_receive(const Message3& msg)
     {
       ++message3_count;
-      etl::send_message(sender, message5);
+      etl::send_message(msg.callback, response);
     }
 
-    void on_receive(etl::imessage_router& sender, const Message4&)
+    void on_receive(const Message4& msg)
     {
       ++message4_count;
-      etl::send_message(sender, message5);
+      etl::send_message(msg.callback, response);
     }
 
-    void on_receive(etl::imessage_router&, const Message5&)
+    void on_receive(const Response&)
     {
       ++message5_count;
     }
 
-    void on_receive_unknown(etl::imessage_router&, const etl::imessage&)
+    void on_receive_unknown(const etl::imessage&)
     {
       ++message_unknown_count;
     }
@@ -154,7 +174,7 @@ namespace
   //***************************************************************************
   // Router that handles messages 1, 2, 4 and 5 and returns nothing.
   //***************************************************************************
-  class RouterB : public etl::message_router<RouterB, Message1, Message2, Message4, Message5>
+  class RouterB : public etl::message_router<RouterB, Message1, Message2, Message4, Response>
   {
   public:
 
@@ -169,33 +189,33 @@ namespace
 
     }
 
-    void on_receive(etl::imessage_router& sender, const Message1&)
+    void on_receive(const Message1& msg)
     {
       ++message1_count;
-      etl::send_message(sender, message5);
+      etl::send_message(msg.callback, response);
     }
 
-    void on_receive(etl::imessage_router& sender, const Message2&)
+    void on_receive(const Message2& msg)
     {
       ++message2_count;
-      etl::send_message(sender, message5);
+      etl::send_message(msg.callback, response);
     }
 
-    void on_receive(etl::imessage_router& sender, const Message4&)
+    void on_receive(const Message4& msg)
     {
       ++message4_count;
-      etl::send_message(sender, message5);
+      etl::send_message(msg.callback, response);
     }
 
-    void on_receive(etl::imessage_router&, const Message5&)
+    void on_receive(const Response&)
     {
       ++message5_count;
     }
 
-    void on_receive_unknown(etl::imessage_router& sender, const etl::imessage&)
+    void on_receive_unknown(const etl::imessage& msg)
     {
       ++message_unknown_count;
-      etl::send_message(sender, message5);
+      //etl::send_message(msg.callback, response);
     }
 
     int message1_count;
@@ -279,12 +299,17 @@ namespace
 
       RouterA router1(ROUTER1);
       RouterB router2(ROUTER2);
-      RouterA sender(ROUTER3);
+      RouterA callback(ROUTER3);
 
       bus1.subscribe(router1);
       bus1.subscribe(router2);
 
-      bus1.receive(sender, message1);
+      Message1 message1(callback);
+      Message2 message2(callback);
+      Message3 message3(callback);
+      Message4 message4(callback);
+
+      bus1.receive(message1);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(0, router1.message2_count);
@@ -299,9 +324,9 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(2, sender.message5_count);
+      CHECK_EQUAL(2, callback.message5_count);
 
-      bus1.receive(sender, message2);
+      bus1.receive(message2);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(1, router1.message2_count);
@@ -316,9 +341,9 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(4, sender.message5_count);
+      CHECK_EQUAL(4, callback.message5_count);
 
-      bus1.receive(sender, message3);
+      bus1.receive(message3);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(1, router1.message2_count);
@@ -333,10 +358,10 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(5, sender.message5_count);
+      CHECK_EQUAL(5, callback.message5_count);
 
       // Use global function.
-      etl::send_message(sender, bus1, message4);
+      etl::send_message(bus1, message4);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(1, router1.message2_count);
@@ -351,7 +376,7 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(7, sender.message5_count);
+      CHECK_EQUAL(7, callback.message5_count);
     }
 
     //*************************************************************************
@@ -361,15 +386,20 @@ namespace
 
       RouterA router1(ROUTER1);
       RouterB router2(ROUTER2);
-      RouterA sender(ROUTER3);
+      RouterA callback(ROUTER3);
 
       bus1.subscribe(router1);
       bus1.subscribe(router2);
 
+      Message1 message1(callback);
+      Message2 message2(callback);
+      Message3 message3(callback);
+      Message4 message4(callback);
+
       // Reference to router sub-type
       etl::imessage_router& irouter = bus1;
 
-      irouter.receive(sender, message1);
+      irouter.receive(message1);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(0, router1.message2_count);
@@ -384,9 +414,9 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(2, sender.message5_count);
+      CHECK_EQUAL(2, callback.message5_count);
 
-      irouter.receive(sender, message2);
+      irouter.receive(message2);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(1, router1.message2_count);
@@ -401,9 +431,9 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(4, sender.message5_count);
+      CHECK_EQUAL(4, callback.message5_count);
 
-      irouter.receive(sender, message3);
+      irouter.receive(message3);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(1, router1.message2_count);
@@ -418,10 +448,10 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(5, sender.message5_count);
+      CHECK_EQUAL(5, callback.message5_count);
 
       // Use global function.
-      etl::send_message(sender, irouter, message4);
+      etl::send_message(irouter, message4);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(1, router1.message2_count);
@@ -436,7 +466,7 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(7, sender.message5_count);
+      CHECK_EQUAL(7, callback.message5_count);
     }
 
     //*************************************************************************
@@ -446,12 +476,17 @@ namespace
 
       RouterA router1(ROUTER1);
       RouterB router2(ROUTER2);
-      RouterA sender(ROUTER3);
+      RouterA callback(ROUTER3);
 
       bus1.subscribe(router1);
       bus1.subscribe(router2);
 
-      bus1.receive(sender, ROUTER1, message1);
+      Message1 message1(callback);
+      Message2 message2(callback);
+      Message3 message3(callback);
+      Message4 message4(callback);
+
+      bus1.receive(ROUTER1, message1);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(0, router1.message2_count);
@@ -466,9 +501,9 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(1, sender.message5_count);
+      CHECK_EQUAL(1, callback.message5_count);
 
-      bus1.receive(sender, ROUTER2, message2);
+      bus1.receive(ROUTER2, message2);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(0, router1.message2_count);
@@ -483,9 +518,9 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(2, sender.message5_count);
+      CHECK_EQUAL(2, callback.message5_count);
 
-      bus1.receive(sender, ROUTER1, message3);
+      bus1.receive(ROUTER1, message3);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(0, router1.message2_count);
@@ -500,10 +535,10 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(3, sender.message5_count);
+      CHECK_EQUAL(3, callback.message5_count);
 
       // Use global function.
-      etl::send_message(sender, bus1, ROUTER2, message4);
+      etl::send_message(bus1, ROUTER2, message4);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(0, router1.message2_count);
@@ -518,10 +553,10 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(4, sender.message5_count);
+      CHECK_EQUAL(4, callback.message5_count);
 
       // Send to a router not subscribed to the bus.
-      bus1.receive(sender, ROUTER5, message1);
+      bus1.receive(ROUTER5, message1);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(0, router1.message2_count);
@@ -536,7 +571,7 @@ namespace
       CHECK_EQUAL(0, router2.message5_count);
       CHECK_EQUAL(0, router2.message_unknown_count);
 
-      CHECK_EQUAL(4, sender.message5_count);
+      CHECK_EQUAL(4, callback.message5_count);
     }
 
     //*************************************************************************
@@ -547,13 +582,17 @@ namespace
       RouterA router1(ROUTER1);
       RouterB router2(ROUTER1);
       RouterB router3(ROUTER2);
-      RouterA sender(ROUTER3);
+      RouterA callback(ROUTER3);
 
       bus1.subscribe(router1);
       bus1.subscribe(router2);
       bus1.subscribe(router3);
 
-      bus1.receive(sender, ROUTER1, message1);
+      Message1 message1(callback);
+      Message2 message2(callback);
+      Message3 message3(callback);
+
+      bus1.receive(ROUTER1, message1);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(0, router1.message2_count);
@@ -574,7 +613,7 @@ namespace
       CHECK_EQUAL(0, router3.message5_count);
       CHECK_EQUAL(0, router3.message_unknown_count);
 
-      CHECK_EQUAL(2, sender.message5_count);
+      CHECK_EQUAL(2, callback.message5_count);
     }
 
     //*************************************************************************
@@ -588,7 +627,7 @@ namespace
       RouterA router3(ROUTER3);
       RouterA router4(ROUTER4);
 
-      RouterA sender(ROUTER5);
+      RouterA callback(ROUTER5);
 
       bus1.subscribe(router1);
       bus1.subscribe(router2);
@@ -597,8 +636,13 @@ namespace
       bus2.subscribe(router3);
       bus2.subscribe(router4);
 
+      Message1 message1(callback);
+      Message2 message2(callback);
+      Message3 message3(callback);
+      Message4 message4(callback);
+
       // Broadcast to bus1
-      bus1.receive(sender, message1);
+      bus1.receive(message1);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(0, router1.message2_count);
@@ -625,10 +669,10 @@ namespace
       CHECK_EQUAL(0, router4.message5_count);
       CHECK_EQUAL(0, router4.message_unknown_count);
 
-      CHECK_EQUAL(4, sender.message5_count);
+      CHECK_EQUAL(4, callback.message5_count);
 
       // Addressed to ROUTER2
-      bus1.receive(sender, ROUTER2, message1);
+      bus1.receive(ROUTER2, message1);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(0, router1.message2_count);
@@ -655,10 +699,10 @@ namespace
       CHECK_EQUAL(0, router4.message5_count);
       CHECK_EQUAL(0, router4.message_unknown_count);
 
-      CHECK_EQUAL(5, sender.message5_count);
+      CHECK_EQUAL(5, callback.message5_count);
 
       // Addressed to ROUTER3 via bus2
-      bus1.receive(sender, ROUTER3, message1);
+      bus1.receive(ROUTER3, message1);
 
       CHECK_EQUAL(1, router1.message1_count);
       CHECK_EQUAL(0, router1.message2_count);
@@ -685,7 +729,7 @@ namespace
       CHECK_EQUAL(0, router4.message5_count);
       CHECK_EQUAL(0, router4.message_unknown_count);
 
-      CHECK_EQUAL(6, sender.message5_count);
+      CHECK_EQUAL(6, callback.message5_count);
     }
 
     //*************************************************************************
@@ -701,7 +745,7 @@ namespace
       RouterA router4a(ROUTER4);
       RouterA router4b(ROUTER4);
 
-      RouterA sender(ROUTER5);
+      RouterA callback(ROUTER5);
 
       bus1.subscribe(router1);
       bus1.subscribe(bus3);
@@ -712,9 +756,11 @@ namespace
       bus3.subscribe(router4b);
       bus3.subscribe(router4a);
 
+      Message1 message1(callback);
+
       call_order = 0;
 
-      bus1.receive(sender, message1);
+      bus1.receive(message1);
 
       CHECK_EQUAL(0, router1.order);
       CHECK_EQUAL(1, router2.order);
diff --git a/test/test_message_router.cpp b/test/test_message_router.cpp
index 8f2ae9f9..3bc2377c 100644
--- a/test/test_message_router.cpp
+++ b/test/test_message_router.cpp
@@ -56,29 +56,49 @@ namespace
 
   struct Message1 : public etl::message<MESSAGE1>
   {
+    Message1(etl::imessage_router& callback_)
+      : callback(callback_)
+    {
+    }
+
+    etl::imessage_router& callback;
   };
 
   struct Message2 : public etl::message<MESSAGE2>
   {
+    Message2(etl::imessage_router& callback_)
+      : callback(callback_)
+    {
+    }
+
+    etl::imessage_router& callback;
   };
 
   struct Message3 : public etl::message<MESSAGE3>
   {
+    Message3(etl::imessage_router& callback_)
+      : callback(callback_)
+    {
+    }
+
+    etl::imessage_router& callback;
     int value[10];
   };
 
   struct Message4 : public etl::message<MESSAGE4>
   {
+    Message4(etl::imessage_router& callback_)
+      : callback(callback_)
+    {
+    }
+
+    etl::imessage_router& callback;
   };
 
   struct Message5 : public etl::message<MESSAGE5>
   {
   };
 
-  Message1 message1;
-  Message2 message2;
-  Message3 message3;
-  Message4 message4;
   Message5 message5;
 
   //***************************************************************************
@@ -100,36 +120,36 @@ namespace
 
     }
 
-    void on_receive(etl::imessage_router& sender, const Message1&)
+    void on_receive(const Message1& msg)
     {
       ++message1_count;
-      etl::send_message(sender, message5);
+      etl::send_message(msg.callback, message5);
     }
 
-    void on_receive(etl::imessage_router& sender, const Message2&)
+    void on_receive(const Message2& msg)
     {
       ++message2_count;
-      etl::send_message(sender, message5);
+      etl::send_message(msg.callback, message5);
     }
 
-    void on_receive(etl::imessage_router& sender, const Message3&)
+    void on_receive(const Message3& msg)
     {
       ++message3_count;
-      etl::send_message(sender, message5);
+      etl::send_message(msg.callback, message5);
     }
 
-    void on_receive(etl::imessage_router& sender, const Message4&)
+    void on_receive(const Message4& msg)
     {
       ++message4_count;
-      etl::send_message(sender, message5);
+      etl::send_message(msg.callback, message5);
     }
 
-    void on_receive(etl::imessage_router&, const Message5&)
+    void on_receive(const Message5&)
     {
       ++callback_count;
     }
 
-    void on_receive_unknown(etl::imessage_router&, const etl::imessage&)
+    void on_receive_unknown(const etl::imessage&)
     {
       ++message_unknown_count;
     }
@@ -161,38 +181,36 @@ namespace
 
     }
 
-    void on_receive(etl::imessage_router& sender, const Message1&)
+    void on_receive(const Message1& msg)
     {
       ++message1_count;
-      sender_id = sender.get_message_router_id();
-      etl::send_message(sender, message5);
+      sender_id = msg.callback.get_message_router_id();
+      etl::send_message(msg.callback, message5);
     }
 
-    void on_receive(etl::imessage_router& sender, const Message2&)
+    void on_receive(const Message2& msg)
     {
       ++message2_count;
-      sender_id = sender.get_message_router_id();
-      etl::send_message(sender, message5);
+      sender_id = msg.callback.get_message_router_id();
+      etl::send_message(msg.callback, message5);
     }
 
-    void on_receive(etl::imessage_router& sender, const Message4&)
+    void on_receive(const Message4& msg)
     {
       ++message4_count;
-      sender_id = sender.get_message_router_id();
-      etl::send_message(sender, message5);
+      sender_id = msg.callback.get_message_router_id();
+      etl::send_message(msg.callback, message5);
     }
 
-    void on_receive(etl::imessage_router& sender, const Message5&)
+    void on_receive(const Message5& msg)
     {
-      sender_id = sender.get_message_router_id();
       ++callback_count;
     }
 
-    void on_receive_unknown(etl::imessage_router& sender, const etl::imessage&)
+    void on_receive_unknown(const etl::imessage&)
     {
       ++message_unknown_count;
       sender_id = 0;
-      etl::send_message(sender, message5);
     }
 
     int message1_count;
@@ -215,11 +233,16 @@ namespace
 
       p_router = &r1;
 
+      Message1 message1(r2);
+      Message2 message2(r2);
+      Message3 message3(r2);
+      Message4 message4(r2);
+
       // CHECK(!r1.is_null_router());
       CHECK(r1.is_producer());
       CHECK(r1.is_consumer());
 
-      p_router->receive(r2, message1);
+      p_router->receive(message1);
       CHECK_EQUAL(1, r1.message1_count);
       CHECK_EQUAL(0, r1.message2_count);
       CHECK_EQUAL(0, r1.message3_count);
@@ -227,7 +250,7 @@ namespace
       CHECK_EQUAL(0, r1.message_unknown_count);
       CHECK_EQUAL(1, r2.callback_count);
 
-      p_router->receive(r2, message2);
+      p_router->receive(message2);
       CHECK_EQUAL(1, r1.message1_count);
       CHECK_EQUAL(1, r1.message2_count);
       CHECK_EQUAL(0, r1.message3_count);
@@ -235,7 +258,7 @@ namespace
       CHECK_EQUAL(0, r1.message_unknown_count);
       CHECK_EQUAL(2, r2.callback_count);
 
-      p_router->receive(r2, message3);
+      p_router->receive(message3);
       CHECK_EQUAL(1, r1.message1_count);
       CHECK_EQUAL(1, r1.message2_count);
       CHECK_EQUAL(1, r1.message3_count);
@@ -243,43 +266,13 @@ namespace
       CHECK_EQUAL(0, r1.message_unknown_count);
       CHECK_EQUAL(3, r2.callback_count);
 
-      p_router->receive(r2, message4);
+      p_router->receive(message4);
       CHECK_EQUAL(1, r1.message1_count);
       CHECK_EQUAL(1, r1.message2_count);
       CHECK_EQUAL(1, r1.message3_count);
       CHECK_EQUAL(1, r1.message4_count);
       CHECK_EQUAL(0, r1.message_unknown_count);
       CHECK_EQUAL(4, r2.callback_count);
-
-      p_router = &r2;
-
-      p_router->receive(r1, message1);
-      CHECK_EQUAL(1, r2.message1_count);
-      CHECK_EQUAL(0, r2.message2_count);
-      CHECK_EQUAL(0, r2.message4_count);
-      CHECK_EQUAL(0, r2.message_unknown_count);
-      CHECK_EQUAL(1, r1.callback_count);
-
-      p_router->receive(r1, message2);
-      CHECK_EQUAL(1, r2.message1_count);
-      CHECK_EQUAL(1, r2.message2_count);
-      CHECK_EQUAL(0, r2.message4_count);
-      CHECK_EQUAL(0, r2.message_unknown_count);
-      CHECK_EQUAL(2, r1.callback_count);
-
-      p_router->receive(r1, message3);
-      CHECK_EQUAL(1, r2.message1_count);
-      CHECK_EQUAL(1, r2.message2_count);
-      CHECK_EQUAL(0, r2.message4_count);
-      CHECK_EQUAL(1, r2.message_unknown_count);
-      CHECK_EQUAL(3, r1.callback_count);
-
-      p_router->receive(r1, message4);
-      CHECK_EQUAL(1, r2.message1_count);
-      CHECK_EQUAL(1, r2.message2_count);
-      CHECK_EQUAL(1, r2.message4_count);
-      CHECK_EQUAL(1, r2.message_unknown_count);
-      CHECK_EQUAL(4, r1.callback_count);
     }
 
     //*************************************************************************
@@ -288,55 +281,60 @@ namespace
       Router2 router;
       etl::null_message_router null_router;
 
+      Message1 message1(null_router);
+      Message2 message2(null_router);
+      Message3 message3(null_router);
+      Message4 message4(null_router);
+
       // CHECK(null_router.is_null_router());
       CHECK(!null_router.is_producer());
       CHECK(!null_router.is_consumer());
 
       // Send from the null router.
-      etl::send_message(null_router, router, message1);
+      etl::send_message(router, message1);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(0, router.message2_count);
       CHECK_EQUAL(0, router.message4_count);
       CHECK_EQUAL(0, router.message_unknown_count);
 
-      etl::send_message(null_router, router, message2);
+      etl::send_message(router, message2);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(0, router.message4_count);
       CHECK_EQUAL(0, router.message_unknown_count);
 
-      etl::send_message(null_router, router, message3);
+      etl::send_message(router, message3);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(0, router.message4_count);
       CHECK_EQUAL(1, router.message_unknown_count);
 
-      etl::send_message(null_router, router, message4);
+      etl::send_message(router, message4);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(1, router.message4_count);
       CHECK_EQUAL(1, router.message_unknown_count);
 
       // Send to the null router.
-      etl::send_message(router, null_router, message1);
+      etl::send_message(null_router, message1);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(1, router.message4_count);
       CHECK_EQUAL(1, router.message_unknown_count);
 
-      etl::send_message(router, null_router, message2);
+      etl::send_message(null_router, message2);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(1, router.message4_count);
       CHECK_EQUAL(1, router.message_unknown_count);
 
-      etl::send_message(router, null_router, message3);
+      etl::send_message(null_router, message3);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(1, router.message4_count);
       CHECK_EQUAL(1, router.message_unknown_count);
 
-      etl::send_message(router, null_router, message4);
+      etl::send_message(null_router, message4);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(1, router.message4_count);
@@ -349,6 +347,11 @@ namespace
       Router2 router;
       etl::message_producer producer(ROUTER3);
 
+      Message1 message1(producer);
+      Message2 message2(producer);
+      Message3 message3(producer);
+      Message4 message4(producer);
+
       // CHECK(!producer.is_null_router());
       CHECK(producer.is_producer());
       CHECK(!producer.is_consumer());
@@ -356,28 +359,28 @@ namespace
       CHECK_EQUAL(0, router.sender_id);
 
       // Send from the producer.
-      etl::send_message(producer, router, message1);
+      etl::send_message(router, message1);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(0, router.message2_count);
       CHECK_EQUAL(0, router.message4_count);
       CHECK_EQUAL(0, router.message_unknown_count);
       CHECK_EQUAL(ROUTER3, router.sender_id);
 
-      etl::send_message(producer, router, message2);
+      etl::send_message(router, message2);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(0, router.message4_count);
       CHECK_EQUAL(0, router.message_unknown_count);
       CHECK_EQUAL(ROUTER3, router.sender_id);
 
-      etl::send_message(producer, router, message3);
+      etl::send_message(router, message3);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(0, router.message4_count);
       CHECK_EQUAL(1, router.message_unknown_count);
       CHECK_EQUAL(0, router.sender_id);
 
-      etl::send_message(producer, router, message4);
+      etl::send_message(router, message4);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(1, router.message4_count);
@@ -385,25 +388,25 @@ namespace
       CHECK_EQUAL(ROUTER3, router.sender_id);
 
       // Send to the producer.
-      etl::send_message(router, producer, message1);
+      etl::send_message(producer, message1);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(1, router.message4_count);
       CHECK_EQUAL(1, router.message_unknown_count);
 
-      etl::send_message(router, producer, message2);
+      etl::send_message(producer, message2);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(1, router.message4_count);
       CHECK_EQUAL(1, router.message_unknown_count);
 
-      etl::send_message(router, producer, message3);
+      etl::send_message(producer, message3);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(1, router.message4_count);
       CHECK_EQUAL(1, router.message_unknown_count);
 
-      etl::send_message(router, producer, message4);
+      etl::send_message(producer, message4);
       CHECK_EQUAL(1, router.message1_count);
       CHECK_EQUAL(1, router.message2_count);
       CHECK_EQUAL(1, router.message4_count);
@@ -415,6 +418,13 @@ namespace
     {
       Router2 r2;
 
+      etl::null_message_router null_router;
+
+      Message1 message1(null_router);
+      Message2 message2(null_router);
+      Message3 message3(null_router);
+      Message4 message4(null_router);
+
       CHECK(r2.accepts(message1));
       CHECK(r2.accepts(message1.get_message_id()));
 
@@ -444,6 +454,11 @@ namespace
 
       etl::imessage* im;
 
+      Message1 message1(r1);
+      Message2 message2(r1);
+      Message3 message3(r1);
+      Message4 message4(r1);
+
       // Queue some messages in the message packet queue.
       im = &message1;
       queue.emplace(*im);
@@ -462,7 +477,7 @@ namespace
       queue.emplace(*im);
 
       etl::imessage& imr1 = queue.front().get();
-      r2.receive(r1, imr1);
+      r2.receive(imr1);
       CHECK_EQUAL(1, r2.message1_count);
       CHECK_EQUAL(0, r2.message2_count);
       CHECK_EQUAL(0, r2.message4_count);
@@ -471,7 +486,7 @@ namespace
       queue.pop();
 
       etl::imessage& imr2 = queue.front().get();
-      r2.receive(r1, imr2);
+      r2.receive(imr2);
       CHECK_EQUAL(1, r2.message1_count);
       CHECK_EQUAL(1, r2.message2_count);
       CHECK_EQUAL(0, r2.message4_count);
@@ -480,7 +495,7 @@ namespace
       queue.pop();
 
       const etl::imessage& imr3 = queue.front().get();
-      r2.receive(r1, imr3);
+      r2.receive(imr3);
       CHECK_EQUAL(1, r2.message1_count);
       CHECK_EQUAL(1, r2.message2_count);
       CHECK_EQUAL(1, r2.message4_count);
@@ -490,7 +505,7 @@ namespace
 
       const Queue& crqueue = queue;
       const etl::imessage& imr4 = crqueue.front().get();
-      r2.receive(r1, imr4);
+      r2.receive(imr4);
       CHECK_EQUAL(1, r2.message1_count);
       CHECK_EQUAL(1, r2.message2_count);
       CHECK_EQUAL(2, r2.message4_count);
@@ -505,6 +520,13 @@ namespace
       Router1 r1;
       Router2 r2;
 
+      etl::null_message_router null_router;
+
+      Message1 message1(r2);
+      Message2 message2(r2);
+      Message3 message3(r2);
+      Message4 message4(r2);
+
       r2.set_successor(r1);
 
       etl::send_message(r2, message1);
diff --git a/test/test_message_timer.cpp b/test/test_message_timer.cpp
index 064ba063..179df367 100644
--- a/test/test_message_timer.cpp
+++ b/test/test_message_timer.cpp
@@ -92,22 +92,22 @@ namespace
 
     }
 
-    void on_receive(etl::imessage_router&, const Message1&)
+    void on_receive(const Message1&)
     {
       message1.push_back(ticks);
     }
 
-    void on_receive(etl::imessage_router&, const Message2&)
+    void on_receive(const Message2&)
     {
       message2.push_back(ticks);
     }
 
-    void on_receive(etl::imessage_router&, const Message3&)
+    void on_receive(const Message3&)
     {
       message3.push_back(ticks);
     }
 
-    void on_receive_unknown(etl::imessage_router&, const etl::imessage&)
+    void on_receive_unknown(const etl::imessage&)
     {
     }
 
diff --git a/test/test_shared_message.cpp b/test/test_shared_message.cpp
index 9fa320cb..258fb49b 100644
--- a/test/test_shared_message.cpp
+++ b/test/test_shared_message.cpp
@@ -80,17 +80,17 @@ namespace
     {
     }
 
-    void on_receive(etl::imessage_router& source, const Message1& message)
+    void on_receive(const Message1& message)
     {
       ++count_message1;
     }
 
-    void on_receive(etl::imessage_router& source, const Message2& message)
+    void on_receive(const Message2& message)
     {
       ++count_message2;
     }
 
-    void on_receive_unknown(etl::imessage_router& source, const etl::imessage& message)
+    void on_receive_unknown(const etl::imessage& message)
     {
 
     }
@@ -118,12 +118,12 @@ namespace
     {
     }
 
-    void on_receive(etl::imessage_router& source, const Message1& message)
+    void on_receive(const Message1& message)
     {
       ++count_message1;
     }
 
-    void on_receive_unknown(etl::imessage_router& source, const etl::imessage& message)
+    void on_receive_unknown(const etl::imessage& message)
     {
       ++count_unknown_message;
     }