diff --git a/src/identity-challenge/challenge-email.cpp b/src/identity-challenge/challenge-email.cpp
index 2775d9e..a439807 100644
--- a/src/identity-challenge/challenge-email.cpp
+++ b/src/identity-challenge/challenge-email.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2017-2019, Regents of the University of California.
+ * Copyright (c) 2017-2020, Regents of the University of California.
  *
  * This file is part of ndncert, a certificate management system based on NDN.
  *