diff --git a/APMrover2/version.h b/APMrover2/version.h
index c0b928bb0c..c3e96f8ee9 100644
--- a/APMrover2/version.h
+++ b/APMrover2/version.h
@@ -6,12 +6,12 @@
 
 #include "ap_version.h"
 
-#define THISFIRMWARE "ArduRover V3.6.0-dev"
+#define THISFIRMWARE "ArduRover V4.0.0-dev"
 
 // the following line is parsed by the autotest scripts
-#define FIRMWARE_VERSION 3,6,0,FIRMWARE_VERSION_TYPE_DEV
+#define FIRMWARE_VERSION 4,6,0,FIRMWARE_VERSION_TYPE_DEV
 
-#define FW_MAJOR 3
-#define FW_MINOR 6
+#define FW_MAJOR 4
+#define FW_MINOR 0
 #define FW_PATCH 0
 #define FW_TYPE FIRMWARE_VERSION_TYPE_DEV