OS X Mavericks 10.9 Developer Preview

The OS X v10.9 Developer Preview supports the following Macs:

- iMac (Mid-2007 or later)
- MacBook (13-inch Aluminum, Late 2008), (13-inch, Early 2009 or later)
- MacBook Pro (13-inch, Mid-2009 or later), (15-inch, Mid/Late 2007 or later), (17-inch, Late 2007 or later)
- MacBook Air (Late 2008 or later)
- Mac Mini (Early 2009 or later)
- Mac Pro (Early 2008 or later)
- Xserve (Early 2009)
 
http://en.wikipedia.org/wiki/OS_X_Mavericks