diff --git a/src/detail/request-encoder.hpp b/src/detail/request-encoder.hpp
index e94571e..a5b80f6 100644
--- a/src/detail/request-encoder.hpp
+++ b/src/detail/request-encoder.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2017-2021, Regents of the University of California.
+ * Copyright (c) 2017-2022, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *
@@ -23,8 +23,7 @@
 
 #include "detail/ca-request-state.hpp"
 
-namespace ndncert {
-namespace requesttlv {
+namespace ndncert::requesttlv {
 
 Block
 encodeApplicationParameters(RequestType requestType, const std::vector<uint8_t>& ecdhPub,
@@ -42,7 +41,6 @@
 decodeDataContent(const Block& content, std::vector<uint8_t>& ecdhKey,
                   std::array<uint8_t, 32>& salt, RequestId& requestId);
 
-} // namespace requesttlv
-} // namespace ndncert
+} // namespace ndncert::requesttlv
 
 #endif // NDNCERT_DETAIL_REQUEST_ENCODER_HPP