Addition of new end-user features was not a primary consideration: its name signified its goal to be a refinement of the previous OS X version, Leopard.Much of the software in Mac OS X was extensively rewritten for this release in order to take advantage fully of modern Macintosh hardware.you can update to Mavericks from your Mac's App Store.
This is also the first Mac OS release since System 7.1.1 that does not support Macs using Power PC processors, as Apple now intends to focus on its current line of Intel-based products.
First, here's the big requirement: Mavericks is free provided you are on 10.6 Snow Leopard, and have updated it to its most recent edition (10.6.8).
If your system is a tad older, and still running Leopard, you have to pay for the Snow Leopard disc, install that physically.
In addition to firmware updates for Mac Book systems and updates for i Photo, Aperture, i OS, and Mountain Lion, Apple has issued security updates for both OS X Snow Leopard and Lion.
The updates should be available via Software Update for systems running their respective operating systems, but they can also be downloaded from the Apple Support downloads pages for the respective updates: OS X Lion Update 10.7.5 Server Combo (1.99GB)OS X Lion Update 10.7.5 Server (1.22GB)OS X Lion Update 10.7.5 Client Combo (1.91GB)OS X Lion Update 10.7.5 Client (1.14GB)Security Update 2012-004 Snow Leopard Server (276.45MB)Security Update 2012-004 Snow Leopard (2.36MB) The security issues addressed by these updates include problems with Web sharing and DNS management services that could result in a denial-of-service attack on the system, and revocation of a compromised root certificate from Trust Wave that could allow an attacker to intercept personal information.