You aren’t the only one, there was an ST update over the weekend which has caused heating setpoint controls to disappear for all devices using it. Stelpro Maestro SMT402 unable to adjust temperature in SmartThings after Controller v. 2.1.19-7
Report it to support@smartthings.com and indicate your urgency so they can prioritize it accordingly.
UPDATE: This issue was resolved during the week of Dec 1st 2020