Mine at least correctly controls the furnace, but the one feature I bought it for -- a thermostat I can control from my iPhone -- barely works. Their app has go

Mine at least correctly controls the furnace, but the one feature I bought it for -- a thermostat I can control from my iPhone -- barely works. Their app has gone downhill with every single release, and it's at least half the time that I get a message saying it can't connect.