diff --git a/proof/hw-mmio_range.adb b/proof/hw-mmio_range.adb
index d96fc4b..9c0da37 100644
--- a/proof/hw-mmio_range.adb
+++ b/proof/hw-mmio_range.adb
@@ -3,7 +3,8 @@
 --
 -- 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; version 2 of the License.
+-- the Free Software Foundation; either version 2 of the License, or
+-- (at your option) any later version.
 --
 -- This program is distributed in the hope that it will be useful,
 -- but WITHOUT ANY WARRANTY; without even the implied warranty of