Modbus updating value over API

I’m trying to write new value to thermostat using API.
I’m able to read temperature using GET /items/{itemname} but i don’t know how to post new temperature setpoint over API.

I’m able to do it normally in OpenHAB but no success over API.

Does anyone know how to do it?

Install the REST Documentation through PaperUI (in the Misc tab). This provides an interactive REST API documentation.

You need to use a POST and have the command as the body of the request and “plain/text” and the data type in the header.