As we discussed over email, If you want a resilient implementation with the best design which will not give you any upgrade or auth tokens issues, then My Next Tstat implementation is for you:
There is a smartapp at my github called WindowOrDoorOpen that will fulfill your use case and more:
The smartapp can set your thermostat(s) to away or turn it off (latter not recommended for locations where a ST outage could cause mold b/c of high humidity).
You can specify the number and frequency of notifications (for your open contacts) and if you want you can also add verbal notifications with your ST connected speakers.