diff --git a/MITL b/MITL
index 38fdbe231..d02b8fe1c 100644
--- a/MITL
+++ b/MITL
@@ -1,4 +1,4 @@
-Copyright (c) 2016 mruby developers
+Copyright (c) 2017 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 6e222057f..76a028ad4 100644
--- a/include/mruby.h
+++ b/include/mruby.h
@@ -1,7 +1,7 @@
 /*
 ** mruby - An embeddable Ruby implementation
 **
-** Copyright (c) mruby developers 2010-2016
+** Copyright (c) mruby developers 2010-2017
 **
 ** Permission is hereby granted, free of charge, to any person obtaining
 ** a copy of this software and associated documentation files (the