I can pair to the MyStat, but it doesn't communicate to the CCU on the 900 MHz network

If you run into this condition, the likely cause is that the CCU CM needs to be updated to a later version. CM has to be min 3.61 and the CCU has to be min 3.3.1. Since as of 9/14/25, the CM does not get updated with a an App Bundle update, it must be updated separately. Initiating the update is a quick process, but the actual update can take up to 30 minutes. 

Follow the instructions in this article to learn how to update the CCU. (Note: be sure to update the CM separately) - Updating System Device Software – ClimaVision