Just wondering about the status of this in Home Assistant? I just received an e-mail from Ecobee yesterday, saying their API authorization methods were changing. Today I find my Ecobee thermostats are offline and no information is available. 
I searched for this myself. The maintainer of the Ecobee integration says there does not appear to be any impact right now. Do a search for other recent posts and there’s a thread where someone links to the GitHub repository for the integration.
EDIT: