Breaking with recent tradition, Mavericks won't drop support for any older Macs.



From ArsTechnica:

Assuming that this continues to be true for OS X 10.9, one MacRumors forum poster has outed the system requirements for Mavericks. Breaking with recent tradition, the list appears to be identical to the compatibility list for OS X 10.8

Each recent OS X release has dropped support for a fairly wide swath of older Macs: OS X 10.6 dropped support for PowerPC Macs, 10.7 dropped support for Intel Macs without 64-bit CPUs, and 10.8 dropped all Macs that didn't support 64-bit EFI. According to this early list, however, any Mac that runs 10.8 should be able to upgrade to 10.9 when it comes out in the fall.

  OS X 10.9 appears to run on any Mac that can run OS X 10.8