diff --git a/COPYING b/COPYING
index c6697cf..c0a6e50 100644
--- a/COPYING
+++ b/COPYING
@@ -1,4 +1,4 @@
-Copyright (c) 2016-2018, Yuki Kobayashi
+Copyright (c) 2016, Yuki Kobayashi
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without