diff --git a/ndn-cpp/node.hpp b/ndn-cpp/node.hpp
index a7e5548..461fe26 100644
--- a/ndn-cpp/node.hpp
+++ b/ndn-cpp/node.hpp
@@ -78,7 +78,7 @@
   
   const ptr_lib::shared_ptr<Transport> &getTransport() { return transport_; }
   
-  virtual void onReceivedElement(unsigned char *element, unsigned int elementLength);
+  void onReceivedElement(const unsigned char *element, unsigned int elementLength);
   
   void shutdown();