I currently have a ST-2E with 2 zones & 2 thermostats. I have a propane fired hot air furnace and a single central air unit. I would like to upgrade my thermostats to smart units which, as I understand it, will require a controller update from ST-2E to NCM-3z.
What should I be comcerned about on the zone dampers and HVAC system side for compatibility? My furnace is only 4 years old but the rest of the system is about 23 years old.