Google announced the end of support for early Nest Thermostats in a support document earlier this year that largely flew under the radar. As of October 25, first and second generation units released in 2011 and 2012, respectively, will be unpaired and removed from the Google Nest or Google Home app.
Users will no longer be able to control their thermostats remotely via their smartphone, receive notifications, or change settings from a mobile device. End-of-support also disables third-party assistants and other cloud-based features including multi-device Eco mode and Nest Protect connectivity.
Was hoping something like Homebridge could be used to still control these, but so far no luck. After the cutoff they can be used manually like a traditional thermostat, which is a surprise coming from Google. I still fear they are going to generate a bunch of ewaste from people replacing them.