diff --git a/v4/v4.ino b/v4/v4.ino
index a1b5f7c..a7ec3f5 100644
--- a/v4/v4.ino
+++ b/v4/v4.ino
@@ -1,4 +1,19 @@
-//© 2024 Philipp Wagner, Riccardo Henning.
+/*
+Copyright (C) 2024  Riccardo Henning and Philipp Wagner
+
+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 3 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
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
 #include <Arduino_USBHostMbed5.h>
 #include <DigitalOut.h>
 #include <FATFileSystem.h>