Apple.MacOSX.Yosemite.10.10.Developer.Preview.Beta.Build.14A238x-iND
The OS X v10.10 Developer Preview supports the following Macs:
iMac (Mid 2007 or newer)
MacBook Air (Late 2008 or newer)
MacBook (Late 2008 Aluminum, or Early 2009 or newer)
Mac mini (Early 2009 or newer)
MacBook Pro (Mid/Late 2007 or newer)
Mac Pro (Early 2008 or newer)
Xserve (Early 2009)