diff --git a/serial/serialcli.py b/serial/serialcli.py
index 622611c..622f737 100644
--- a/serial/serialcli.py
+++ b/serial/serialcli.py
@@ -4,7 +4,8 @@
 # see __init__.py
 #
 # (C) 2008 Chris Liechti <cliechti@gmx.net>
-# this is distributed under a free software license, see license.txt
+#
+# SPDX-License-Identifier:    BSD-3-Clause
 
 import clr
 import System