One of the first requirements is that you will need to have OS X Snow Leopard or later. OS X Snow Leopard or later is required because it needs to be downloaded via the Mac App Store. In addition, the system requirements call for 64-bit, Intel-based Macs with 8GB of free disk space for installation.
The list of Macs that will run Mavericks is similar to those that were able to use OS X 10.8 Mountain Lion.The following is a list of Macs and OS X Mavericks compatibility:
- MacBook Pro - you'll need to have either a 13-inch from mid-2009, 15-inch from mid/late 2007 or 17-inch from late 2007 or later
- MacBook - 13-inch 2008 from 2008 in aluminum, early 2009 or later
- iMac - it needs to be mid 2007 or newer
- MacBook Air - it needs to be at 2008 or newer
- Mac Mini - it needs to be early 2009 or newer
- Mac Pro - it needs to be early 2008 or newer
- Xserve - early 2009
The list of Macs that won't be able to upgrade to Mavericks is long. MacBooks pre 2008, pre mid 2007 MacBook Pros and Mac Mini/iMac and most notably the original MacBook Air will not be able to be upgraded.
References:
http://appleinsider.com/articles/13/06/11/macs-capable-of-running-os-x-mountain-lion-likely-compatible-with-os-x-109-mavericks
http://www.techradar.com/us/news/computing/apple/os-x-mountain-lion-compatibility-will-your-mac-take-it-1064310