Apple has been pushing boundaries pretty hard with regards to software upgrade pricing for the last several years. The last few OS X upgrades have been very cheap, often $30 or less. Today takes it even lower, however, as they’re bringing it down to just $0.
Perhaps more impressive than the fact that the upgrade is free for users of Mac OS X Mountain Lion is the fact that it’s free for literally anyone who can run it.
The compatibility stretches back to 2007 for iMacs, and 2009 for Mac Minis, with MacBooks of various flavors coming in along the edges.
Any Mac in the list that is currently running Mountain Lion – or Lion – or even Snow Leopard – can download the upgrade from the Mac App Store free of charge. It’ll be available later today.
What’s nice about this upgrade – and it’s a massive upgrade for users of, say, Snow Leopard or Lion – is that you can download and install it in place. Some Windows installations often support this, but it can be fairly buggy, with missing or broken applications after the installation. With Mavericks, you should be able to upgrade your Mac without losing any of your installed software or files.
Despite this, we absolutely recommend that you back all of your important data up before attempting the installation, just to be safe.