I spoke to Drayton today about a related problem with their app, the temperature history from each TRV has stopped working. They were aware of the problem and was connected to a hub firmware update in the last day or so. I guess this might be the reason for the sudden failure of the Domoticz plugin.

Something has definitely changed, my plugin is not working either. I have the error "Error: Drayton Wiser hardware (9) thread seems to have ended unexpectedly" The IDX of the Drayton hardware is 9. I tried deleting the hardware and reinstalling in Domoticz, but to no avail.

Just installed your plugin and it's working fine...thanks.
For info, and for other potential users of the plugin, to get it working I had to update my Rasp Pi to install python3 and python3-dev as per the Domoticz wiki (https://www.domoticz.com/wiki/Using_Python_plugins). I also had "adding devices ...