Based on the naming convention, the typically refers to the Tuya TR6703 Smart Thermostat (often manufactured by companies like SASWELL or MOES). It is a touchscreen thermostat used for water heating, electric heating, or gas boiler control.
The safest and most reliable source is the official website of the hardware manufacturer (often brands like Tower, High-Flying, or USR). Most provide these utilities in their "Download" or "Support" sections. tr6703 v5 software free