diff --git a/ecal/core/src/io/udp/fragmentation/snd_fragments.cpp b/ecal/core/src/io/udp/fragmentation/snd_fragments.cpp
index a4a8320805..4cfafa26a4 100644
--- a/ecal/core/src/io/udp/fragmentation/snd_fragments.cpp
+++ b/ecal/core/src/io/udp/fragmentation/snd_fragments.cpp
@@ -79,7 +79,7 @@ namespace IO
       return (0);
     }
 
-    size_t SendFragmentedMessage(char* buf_, size_t buf_len_, long bandwidth_, TransmitCallbackT transmit_cb_)
+    size_t SendFragmentedMessage(char* buf_, size_t buf_len_, long bandwidth_, const TransmitCallbackT& transmit_cb_)
     {
       if (buf_ == nullptr) return(0);
 
diff --git a/ecal/core/src/io/udp/fragmentation/snd_fragments.h b/ecal/core/src/io/udp/fragmentation/snd_fragments.h
index 83adb1b78d..3638e7070d 100644
--- a/ecal/core/src/io/udp/fragmentation/snd_fragments.h
+++ b/ecal/core/src/io/udp/fragmentation/snd_fragments.h
@@ -39,6 +39,6 @@ namespace IO
     size_t CreateSampleBuffer(const std::string& sample_name_, const eCAL::pb::Sample& ecal_sample_, std::vector<char>& payload_);
 
     using TransmitCallbackT = std::function<size_t(const void*, const size_t)>;
-    size_t SendFragmentedMessage(char* buf_, size_t buf_len_, long bandwidth_, TransmitCallbackT transmit_cb_);
+    size_t SendFragmentedMessage(char* buf_, size_t buf_len_, long bandwidth_, const TransmitCallbackT& transmit_cb_);
   }
 }
diff --git a/ecal/core/src/io/udp/sendreceive/udp_receiver_asio.cpp b/ecal/core/src/io/udp/sendreceive/udp_receiver_asio.cpp
index e14268a53c..51b57e2d65 100644
--- a/ecal/core/src/io/udp/sendreceive/udp_receiver_asio.cpp
+++ b/ecal/core/src/io/udp/sendreceive/udp_receiver_asio.cpp
@@ -129,14 +129,6 @@ namespace IO
             return(false);
           }
         }
-
-#ifdef ECAL_JOIN_MULTICAST_TWICE
-        // this is a very bad workaround because of an identified bug on a specific embedded device
-        // we join the multicast group multiple times otherwise the socket will not receive any data
-        std::cerr << "eCAL was compiled with ECAL_JOIN_MULTICAST_TWICE" << std::endl;
-        m_socket.set_option(asio::ip::multicast::leave_group(asio::ip::make_address(ipaddr_)));
-        m_socket.set_option(asio::ip::multicast::join_group(asio::ip::make_address(ipaddr_)));
-#endif // ECAL_JOIN_MULTICAST_TWICE
       }
       return(true);
     }
diff --git a/ecal/core/src/io/udp/sendreceive/udp_receiver_asio.h b/ecal/core/src/io/udp/sendreceive/udp_receiver_asio.h
index 28dd8362ad..2c1d3fe0f7 100644
--- a/ecal/core/src/io/udp/sendreceive/udp_receiver_asio.h
+++ b/ecal/core/src/io/udp/sendreceive/udp_receiver_asio.h
@@ -41,7 +41,7 @@ namespace IO
 
       // this virtual function is called during construction/destruction,
       // so, mark it as final to ensure that no derived classes override it.
-      bool AddMultiCastGroup(const char* ipaddr_) final override;
+      bool AddMultiCastGroup(const char* ipaddr_) final;
       bool RemMultiCastGroup(const char* ipaddr_) override;
 
       size_t Receive(char* buf_, size_t len_, int timeout_, ::sockaddr_in* address_ = nullptr) override;
diff --git a/ecal/core/src/io/udp/sendreceive/udp_receiver_impl.h b/ecal/core/src/io/udp/sendreceive/udp_receiver_impl.h
deleted file mode 100644
index b05434d292..0000000000
--- a/ecal/core/src/io/udp/sendreceive/udp_receiver_impl.h
+++ /dev/null
@@ -1,47 +0,0 @@
-/* ========================= eCAL LICENSE =================================
- *
- * Copyright (C) 2016 - 2019 Continental Corporation
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- * ========================= eCAL LICENSE =================================
-*/
-
-#pragma once
-
-#include "udp_receiver.h"
-
-namespace eCAL
-{
-  ////////////////////////////////////////////////////////
-  // udp receiver class implementation
-  ////////////////////////////////////////////////////////
-  class CUDPReceiverImpl
-  {
-  public:
-    CUDPReceiverImpl(const SReceiverAttr& /*attr_*/) {};
-    // We don't technically need a virtual destructor, if we are working with shared_ptrs...
-    virtual ~CUDPReceiverImpl() = default;
-
-    // Delete copy / move operations to prevent slicing
-    CUDPReceiverImpl(CUDPReceiverImpl&&) = delete;
-    CUDPReceiverImpl& operator=(CUDPReceiverImpl&&) = delete;
-    CUDPReceiverImpl(const CUDPReceiverImpl&) = delete;
-    CUDPReceiverImpl& operator=(const CUDPReceiverImpl&) = delete;
-
-    virtual bool AddMultiCastGroup(const char* ipaddr_) = 0;
-    virtual bool RemMultiCastGroup(const char* ipaddr_) = 0;
-
-    virtual size_t Receive(char* buf_, size_t len_, int timeout_, ::sockaddr_in* address_ = nullptr) = 0;
-  };
-}
diff --git a/ecal/core/src/io/udp/sendreceive/udp_sender.cpp b/ecal/core/src/io/udp/sendreceive/udp_sender.cpp
index 33c8fe9928..5bca08c93d 100644
--- a/ecal/core/src/io/udp/sendreceive/udp_sender.cpp
+++ b/ecal/core/src/io/udp/sendreceive/udp_sender.cpp
@@ -24,7 +24,6 @@
 #include "udp_sender.h"
 
 #include <iostream>
-#include <functional>
 
 #ifdef _MSC_VER
 #pragma warning(push)