Mountain Lion may be the new code name for the next major upgrade to Apple's OS X, but for some older Mac machines the name might as well be mud. According to the TUAW web site, an anonymous developer has sent out a list of which Macs won't be able to run Mountain Lion.
The list includes the first version of the Macbook Air, which was launched just over four years ago. Yes, that means all of those early adopters to the thin and light notebook are going to have to be satisfied with the current Lion version of OS X.
Mountain Lion also can't be used on iMacs made in late 2006, all Macbook Pros made prior to July 2007, nearly all of the Macbooks with the plastic body casing and the Xserves machines made in late 2006 and early 2008.
As we previously reported, the release of Mountain Lion sometime this summer will come just one year after the release of Lion for Mac owners. Apple has decided to launch major OS X updates every year from now on via a download only business model. That means in 2013 you can expect to see a 10.9 update that will send another batch of older Macs to the update phantom zone.