diff --git a/README.md b/README.md
index bc8fe3b..b663cd5 100644
--- a/README.md
+++ b/README.md
@@ -185,5 +185,5 @@ Default 3.0MHz. Applicable range 1.0MHz to 5.0MHz.
 
 ### License
 
-Copyright © 2015-2022 Takuji Ebinuma  
+Copyright © 2015-2023 Takuji Ebinuma  
 Distributed under the [MIT License](http://www.opensource.org/licenses/mit-license.php).