Update number M405FDDU2BTB5 contains both the newest version of the OS as well as March 2020 security patch. It weights 1.7 gigabyte and is available from the Settings > Software Update menu. Sadly, instead of the full-fledged One UI 2.0, overlay, all that Galaxy M40 gets is One UI Core 2.0. This means that the device will miss on some features.