updated 11:29 pm EST, Tue December 17, 2013
Free upgrade, wide compatibility for Mavericks designed to encourage upgrading
Last week, Apple updated its Safari browser for Lion, Mountain Lion and Mavericks -- but for the first time since 2010, did not include an update for the Snow Leopard version, last updated to 5.1.10. The move may signal that Apple is winding down support for the three-generations-back OS, which remains the third-most popular version of OS X behind the current version, Mavericks and 10.8 Mountain Lion (respectively).
The omission may not mean the end of all Snow Leopard updates, however. The 10.6 OS was the first to include the Mac App Store and the malware protector XProtect, and both of these may continue to get updates for security purposes -- though Snow Leopard has actually been supported past its normal retirement date, in part because until Mavericks came out, it was the second most-popular version of Mac OS X. In many ways, Snow Leopard was the reference platform from which Lion, Mountain Lion, and Mavericks are built.
Traditionally, Apple only offers active (but varying) levels of support and updates for its three most recent OS versions -- which would now make the "senior" one Lion (10.7), released in 2011. Since Snow Leopard, Apple has adopted a policy of yearly new OS versions that are less feature-laden but more routine (and dramatically lower-cost), with each building on the previous one's strengths (or in some cases, revising unpopular changes) rather than focusing on "flashy" features to grab user's attention. Many of the biggest changes in Mavericks, for example, are behind the scenes or mostly affect mobile users.
Apple also extended the life of OS X Tiger (10.4) due to its popularity beyond its normal lifespan, providing an additional 13 months of updates for Safari and other key elements (or security updates) such as iTunes and QuickTime. It is possible that Snow Leopard will receive a diminishing number of further updates to assist with compatibility, but clearly the company designed Mavericks to be as widely compatible as possible as its preferred method of encouraging remaining users to upgrade. Mavericks is compatible with some machine as old as 2007, an unusual six-year hardware compatibility. The update is also free of charge, further encouraging upgraders.
Snow Leopard is still used on around 20 percent of active Macs, with Lion accounting for about 18 percent and the latest version, Mavericks, leading with about a third of all Macs in use (leaving Mountain Lion with about 25 percent, and older versions combined registering around four percent). It was the last OS version to support PowerPC-exclusive apps, which may account for some of its longevity. With few exceptions, developers and users have moved on to Universal or Intel-native applications and alternatives (that are often superior in that they take advantage of more modern technologies and security enhancements, like 64-bit compatibility and sandboxing).
Apple currently still sells Snow Leopard on DVD for the dwindling percentage of early Intel Mac customers who never upgraded, since running Snow Leopard is the minimum needed to access the Mac App Store, from which most users can further upgrade to Mavericks. The lack of any new updates for Snow Leopard in the past few months signals that Apple will not continue to offer the retrograde OS version indefinitely, allowing natural upgrading and attrition to push Snow Leopard user numbers down to a minimal percentage by the time the next OS upgrade cycle comes around.