How do I know which Honeywell app to use?

Knowing which Honeywell app to use can be confusing because Honeywell has released several apps over the years due to corporate spin-offs. The general rule is that almost all current Wi-Fi enabled models should use the Honeywell Home app, which is now also branded as Resideo in some app stores. Use Honeywell Home or Resideo app if you have T5, T5+, T6 Pro Wi-Fi, T9, T10, RTH9585WF, RTH6580WF, C1, C2, Lyric T5, Lyric T6, Lyric Round, or any thermostat that mentions Lyric or Home. Use the older Total Connect Comfort or TCC app only if you have very old RedLINK or older Wi-Fi models that specifically state in their manual to use TCC, or if your thermostat was installed by a utility program that uses TCC. If you have a commercial or professional Pro Series thermostat installed by an HVAC contractor, it might use the Honeywell Home Pro app or need to be set up by the installer. The easiest way to confirm is to look at the back of your thermostat for a sticker that says Get the Honeywell Home app or search your model number on the Honeywell Home support website, which will link directly to the correct app. Avoid third-party apps that charge money and claim to control Honeywell devices.