--- a/master/mailbox.c	Mon Apr 24 10:47:03 2006 +0000
+++ b/master/mailbox.c	Mon May 29 09:08:56 2006 +0000
@@ -8,7 +8,8 @@
  *
  *  The IgH EtherCAT Master 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.
+ *  as published by the Free Software Foundation; either version 2 of the
+ *  License, or (at your option) any later version.
  *
  *  The IgH EtherCAT Master is distributed in the hope that it will be
  *  useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -19,6 +20,15 @@
  *  along with the IgH EtherCAT Master; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  *
+ *  The right to use EtherCAT Technology is granted and comes free of
+ *  charge under condition of compatibility of product made by
+ *  Licensee. People intending to distribute/sell products based on the
+ *  code, have to sign an agreement to guarantee that products using
+ *  software based on IgH EtherCAT master stay compatible with the actual
+ *  EtherCAT specification (which are released themselves as an open
+ *  standard) as the (only) precondition to have the right to use EtherCAT
+ *  Technology, IP and trade marks.
+ *
  *****************************************************************************/
 
 /**