diff --git a/tools/chunks/catchunks/discover-version.hpp b/tools/chunks/catchunks/discover-version.hpp
index bb6a477..c34ff5e 100644
--- a/tools/chunks/catchunks/discover-version.hpp
+++ b/tools/chunks/catchunks/discover-version.hpp
@@ -1,8 +1,8 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2016,  Regents of the University of California,
- *                      Colorado State University,
- *                      University Pierre & Marie Curie, Sorbonne University.
+/*
+ * Copyright (c) 2016-2017, Regents of the University of California,
+ *                          Colorado State University,
+ *                          University Pierre & Marie Curie, Sorbonne University.
  *
  * This file is part of ndn-tools (Named Data Networking Essential Tools).
  * See AUTHORS.md for complete list of ndn-tools authors and contributors.
@@ -64,6 +64,9 @@
    */
   DiscoverVersion(const Name& prefix, Face& face, const Options& options);
 
+  virtual
+  ~DiscoverVersion();
+
   /**
    * @brief identify the latest Data version published.
    */