u/LastKnightOfCydonia

Title, I took the unit off the wall to see what was going on for wiring for it. House was built in 1961, heating only from a boiler/hydronic baseboard heating. There are two wires that are hooked up to the thermostat, red and blue, and a third white wire that was folded back and pushed into the wall. If I want to go about replacing it with a new thermostat, is digital/smart out of the question?

The color coding doesn't seem to match what the guides online would suggest as to what is power, heat, or common wires, if there truly is a common wire.

Would I need to call out the HVAC team that installed the new boiler this winter to see about wiring it properly, or could I conceivably do it myself?