I've got a 2927 using a Temper1F USB thermometer which works okay, however purchased a Temper 'Gold' model to go in an 2962 but will not work. I know there's differences with chipset and FW versions on various USB thermometers hence why Draytek dropped full support for them but wondering what people's experiences are of successfully getting one to work. Presumably the 'Temper1F' variant either has a different chipset or compatible FW version to work in Draytek units? Just found a Temper1F model USB thermometer and going to give that a whirl in the 2926 as clearly they work in the 2927!

This article mentioned the Gold Temper unit as 'possibly' working but gave no guarantees, certainly doesn't seem to work with 2927 or 2962 units.
https://www.draytek.co.uk/support/guides/kb-usb-thermometer-source