diff --git a/src/gsm/abis_nm.c b/src/gsm/abis_nm.c
index 7207fb9..8a3886d 100644
--- a/src/gsm/abis_nm.c
+++ b/src/gsm/abis_nm.c
@@ -1,8 +1,10 @@
 /*
- * (C) 2008-2011 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2008-2014,2017 by Harald Welte <laforge@gnumonks.org>
  *
  * 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