“That means owners of the Nest thermostats released in 2011 and 2012 (as well as the version released in Europe in 2014) won’t receive updates, and their devices will no longer be supported in the Nest and Home apps.”
Google ends support for the first two Nest thermostats in October. They keep local controls and lose the app. Google also stops launching new Nest products in Europe. The smart part of the smart thermostat expires.