The serial number can be found on the type plate of the Thermomix Friend®, which is located on the underside of the device.
The software version of the Thermomix Friend® can be checked via the Thermomix Friend® app (available for smartphones on Google Play and the Apple App Store). Simply download it to your smartphone, pair it once, and the app will tell you whether a new software version is available.
If you own a TM6, it will also tell you when a new software version is available.