diff --git a/libraries/AP_AHRS/AP_AHRS.cpp b/libraries/AP_AHRS/AP_AHRS.cpp
index 04adc4c7f0..8242331c69 100644
--- a/libraries/AP_AHRS/AP_AHRS.cpp
+++ b/libraries/AP_AHRS/AP_AHRS.cpp
@@ -1,10 +1,18 @@
 /*
-	APM_AHRS.cpp
-
-	This library is free software; you can redistribute it and/or
-	modify it under the terms of the GNU Lesser General Public License
-	as published by the Free Software Foundation; either version 2.1
-	of the License, or (at your option) any later version.
+  APM_AHRS.cpp
+
+  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 <AP_AHRS.h>
 #include <AP_HAL.h>
diff --git a/libraries/AP_AHRS/AP_AHRS_DCM.cpp b/libraries/AP_AHRS/AP_AHRS_DCM.cpp
index 3039036af8..c41dcd4cff 100644
--- a/libraries/AP_AHRS/AP_AHRS_DCM.cpp
+++ b/libraries/AP_AHRS/AP_AHRS_DCM.cpp
@@ -7,11 +7,19 @@
  *       Based on DCM code by Doug Weibel, Jordi Muņoz and Jose Julio. DIYDrones.com
  *
  *       Adapted for the general ArduPilot AHRS interface by Andrew Tridgell
- *
- *       This library is free software; you can redistribute it and/or
- *       modify it under the terms of the GNU Lesser General Public License
- *       as published by the Free Software Foundation; either version 2.1
- *       of the License, or (at your option) any later version.
+
+  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 <AP_AHRS.h>
 #include <AP_HAL.h>
diff --git a/libraries/AP_AHRS/AP_AHRS_HIL.cpp b/libraries/AP_AHRS/AP_AHRS_HIL.cpp
index b2eb8ca5dc..25be381039 100644
--- a/libraries/AP_AHRS/AP_AHRS_HIL.cpp
+++ b/libraries/AP_AHRS/AP_AHRS_HIL.cpp
@@ -2,12 +2,19 @@
  *       APM_AHRS_HIL.cpp
  *
  *       Hardware in the loop AHRS object
- *
- *       This library is free software; you can redistribute it and/or
- *       modify it under the terms of the GNU Lesser General Public
- *       License as published by the Free Software Foundation; either
- *       version 2.1 of the License, or (at your option) any later
- *       version.
+
+  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 <AP_AHRS.h>
diff --git a/libraries/AP_AHRS/AP_AHRS_MPU6000.cpp b/libraries/AP_AHRS/AP_AHRS_MPU6000.cpp
index 8629359053..cd8e334a1e 100644
--- a/libraries/AP_AHRS/AP_AHRS_MPU6000.cpp
+++ b/libraries/AP_AHRS/AP_AHRS_MPU6000.cpp
@@ -5,11 +5,19 @@
  *       AHRS system using MPU6000's internal calculations
  *
  *       Adapted for the general ArduPilot AHRS interface by Andrew Tridgell
- *
- *       This library is free software; you can redistribute it and/or
- *       modify it under the terms of the GNU Lesser General Public License
- *       as published by the Free Software Foundation; either version 2.1
- *       of the License, or (at your option) any later version.
+
+  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 <AP_AHRS.h>
 #include <AP_HAL.h>