Digital Thermostat Can I Replace A Digital Thermostat Without Turning Off The Electric Power To The House Heater?

Can I replace a digital thermostat without turning off the electric power to the house heater? - digital thermostat

I heat my house with a gas-fired condensing boilers, hot water (Crown). My digital thermostat is dysfunctional and needs to be replaced. I bought a 7-day programmable thermostat RiteTemp similar to the river, takes 2 AA batteries. There are 3 son of the old thermostat connected. Should I cut power to the heating system to replace the thermostat? If not, there is a risk of electrical shock or damage to hardware?