A number of old Mac Mountain Lion cannot be upgraded

Apple has just said, not your Mac can be upgraded to version OS X Mountain Lion, upcoming operating system in July.

Accordingly, these products receive the ability to upgrade included iMac (mid 2007 onwards), MacBook (late 2008 with aluminum casing, or early 2009 onwards), MacBook Pro (mid and late 2007 onwards), MacBook Air (late 2008 onwards), Mac mini (early 2009 onwards), Mac Pro (early 2008 onwards), Xserve (early 2009).

Although not giving any specific reasons, but according to ArsTechnica graphic on 64 bit systems is the primary cause by the older line of products listed above only using 32 bit graphic driver

The decision of Apple also meant that the airline will type the old line in supporting upgrades to encourage users to switch to the newer product lines. Although the company remained committed to release patches for their old product line.

Known as Mountain Lion will officially be released on April 7 via Mac App Store format upgrade for $ 19.99 USD.