diff --git a/mdfour.c b/mdfour.c
index e832fc7..52c2fa0 100644
--- a/mdfour.c
+++ b/mdfour.c
@@ -3,7 +3,7 @@
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
+ * the Free Software Foundation; either version 3 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,