diff --git a/CMakeLists.txt b/CMakeLists.txt
index c0aaad64..a7a662fd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -20,7 +20,7 @@ enable_testing()
 set(CMAKE_C_STANDARD_REQUIRED ON)
 set(CMAKE_C_STANDARD          99)
 project(SALMON
-        VERSION   2.2.0
+        VERSION   2.2.1
         LANGUAGES Fortran C
         )
 
diff --git a/README.md b/README.md
index cc085fc8..68b33755 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ http://salmon-tddft.jp/
 
 SALMON is available under Apache License version 2.0.
 
-    Copyright 2017-2023 SALMON developers
+    Copyright 2017-2024 SALMON developers
 
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
diff --git a/configure.py b/configure.py
index 0b5e3ae2..c1ecddbb 100755
--- a/configure.py
+++ b/configure.py
@@ -1,6 +1,6 @@
 #! /usr/bin/env python
 #
-#   Copyright 2017-2023 SALMON developers
+#   Copyright 2017-2024 SALMON developers
 #
 #   Licensed under the Apache License, Version 2.0 (the "License");
 #   you may not use this file except in compliance with the License.