Google posted in the Google Maps Help forums that on January 11, 2017 they will be discontinuing the Google Earth API and also sunsetting Google Earth 4.
Google wrote, "in December 2014, we announced that we would be deprecating the Google Earth API." "The Earth API was built on the NPAPI plugin framework which most modern browsers no longer support. This has made building applications that leverage the Earth API untenable for developers. The API was kept alive for an extra year so developers had time to choose alternatives, but we will be officially taking it down in January," Google added.
Google Earth, the application, is now up to version 7.x, so they are going to stop supporting version 4. They recommend those using version 4, upgrade to version 7.x.
Forum discussion at Google Maps Help.
