It looks like September will bring a host of improvements to Google's Chromecast. In addition to upgraded hardware, the search giant is reportedly adding Spotify support to Chromecast, according to documents seen by 9to5Google. Spotify support is likely to be announced at Google's event on September 29th, where it's also rumored to be announcing a second-generation Chromecast dongle, and two new Nexus phones.
Chromecast can already stream music from a number of sources, including Google Play Music, Pandora, Rdio, and Plex. Spotify was the largest of the streaming music services missing from that list, but the expected announcement should make Google's Chromecast dongle a more enticing option for home streaming — particularly if the new model does indeed allow you to stream to any speaker in your house through the yet-to-be-announced Chromecast Audio service.