diff --git a/debug/hw-debug.adb b/debug/hw-debug.adb
index 3ffa9b5..60968e1 100644
--- a/debug/hw-debug.adb
+++ b/debug/hw-debug.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
diff --git a/debug/hw-debug.ads b/debug/hw-debug.ads
index fd8ce9c..adf61fb 100644
--- a/debug/hw-debug.ads
+++ b/debug/hw-debug.ads
@@ -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
diff --git a/debug/null/hw-debug_sink.ads b/debug/null/hw-debug_sink.ads
index dcd2dd1..065ce4b 100644
--- a/debug/null/hw-debug_sink.ads
+++ b/debug/null/hw-debug_sink.ads
@@ -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
diff --git a/debug/text_io/hw-debug_sink.ads b/debug/text_io/hw-debug_sink.ads
index 2f0b2d2..fa02922 100644
--- a/debug/text_io/hw-debug_sink.ads
+++ b/debug/text_io/hw-debug_sink.ads
@@ -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