Apple announces OS X 10.10 Yosemite with new interface, enhanced apps & continuity
Named after the California national park, Yosemite will be available later this fall, and end users will be able to sign up for a public beta program in the summer. As with Mavericks, the Yosemite update will be free.
Story added 2. June 2014, content source with full text you can find at link above.