diff --git a/src/gsm/lapdm.c b/src/gsm/lapdm.c
index db950a6..5efe755 100644
--- a/src/gsm/lapdm.c
+++ b/src/gsm/lapdm.c
@@ -1,11 +1,14 @@
 /*! \file lapdm.c
  * GSM LAPDm (TS 04.06) implementation. */
 /*
- * (C) 2010-2011 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2010-2017 by Harald Welte <laforge@gnumonks.org>
  * (C) 2010-2011 by Andreas Eversberg <jolly@eversberg.eu>
+ * (C) 2014-2016 by sysmocom - s.f.m.c GmbH
  *
  * All Rights Reserved
  *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
  * 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