diff --git a/LICENSE b/LICENSE
index 6881f4df6..7461282a3 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) 2010-2022 mruby developers
+Copyright (c) 2010-2023 mruby developers
 
 Permission is hereby granted, free of charge, to any person obtaining a
 copy of this software and associated documentation files (the "Software"),
diff --git a/include/mruby.h b/include/mruby.h
index e7faf53c1..349dacccb 100644
--- a/include/mruby.h
+++ b/include/mruby.h
@@ -1,7 +1,7 @@
 /*
 ** mruby - An embeddable Ruby implementation
 **
-** Copyright (c) mruby developers 2010-2022
+** Copyright (c) mruby developers 2010-2023
 **
 ** Permission is hereby granted, free of charge, to any person obtaining
 ** a copy of this software and associated documentation files (the