[BT-6709] version 1.6 -> 1.6b

config/board_bt6709.h

@@ -55,7 +55,7 @@ WDG_PIN(X)
 #ifdef ORDER_MTS
 #define VERSION                         "1.3"
 #else
-#define VERSION                         "1.6"
+#define VERSION                         "1.6b"
 #endif
 
 /**