Samsung is sending out a new software update to the Galaxy M40 units sold in India. This arrives over-the-air as a 366MB download, and upon installation will make your phone run software version M405FDDU1ASH1.
The August security patch level is integrated, and you also get the dedicated QR scanner feature that lets you scan codes whenever the camera is pointed at them, without needing to install any third-party apps for this purpose. A lot of Samsung devices have been getting this lately.
The same goes for the dedicated camera Night mode. This too has landed on the Galaxy M40, following its appearance on Galaxy flagships. As the name implies, you can simply switch to this mode whenever you like in order to capture a long-exposure shot with a steady hand.
If you bought your M40 in India and haven't yet received the update notification, you can perhaps manually check for its availability by going to Settings > Software update > Download and install.