You can take the model number from your furnace, and go to the makers web site to see if there are any optional t'stats available. But the digital t'stats, I've delt with have had 3 or more wires. 12v +, 12v-, and a signal wire to the control board on the furnace. So depending on your furnace , you may be stuck with what you have.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.