diff --git a/src/access-manager.hpp b/src/access-manager.hpp
index 22dc2cc..5bfb0b1 100644
--- a/src/access-manager.hpp
+++ b/src/access-manager.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2021, Regents of the University of California
+ * Copyright (c) 2014-2022, Regents of the University of California
  *
  * NAC library is free software: you can redistribute it and/or modify it under the
  * terms of the GNU Lesser General Public License as published by the Free Software
@@ -24,8 +24,7 @@
 
 #include <ndn-cxx/face.hpp>
 
-namespace ndn {
-namespace nac {
+namespace ndn::nac {
 
 /**
  * @brief Access Manager
@@ -131,7 +130,6 @@
   ScopedRegisteredPrefixHandle m_kdkReg;
 };
 
-} // namespace nac
-} // namespace ndn
+} // namespace ndn::nac
 
 #endif // NDN_NAC_ACCESS_MANAGER_HPP