Device not recognized: HorstmannControlsLimited Thermostat

Device: HorstmannControlsLimited Thermostat
homee Version: 2.9.2 (8ff106b)
Web App Version: 2.9.2 (#05e8eca)
How is the device behaving? (Screenshot would be good :blush:):

This is a Horstman ASR-2W (also know as Secure SSR303).
It is a boiler receiver controller.
It is working, but the toggle (on / off) is not shown as a main device option.

I assume it’s not a bug but the device is simply not supported yet. You can find the supported devices on the homepage It does not mean that other devices do not work but usually you will get this error. If you want the device be supported, you need to open a request/proposal in the correct part of this board. If you get enough likes, it might get included somewhen.