Last month, Apple began offering a "last compatible" version feature in its iOS App Store, giving developers the option of offering users running pre-iOS 7 operating systems on their iOS devices the ability to download older versions of their apps compatible with those devices and operating systems.
With today's launch of OS X Mavericks, Apple has notified Mac developers that a similar feature is coming to the Mac App Store, allowing users to continue using older versions of apps on their Macs that may not be compatible with Mavericks.
Users who have already purchased your Mac app are now able to download previous versions, allowing them to use your app with Macs that may no longer be supported by OS X Mavericks.
If you do not want previous versions of your app to be available for download as a previous purchase, for example due to a usability or legal issue, you can manage their availability in the Rights and Pricing section of the Manage Your Apps module on iTunes Connect. To exclude a specific version, click “Manage iCloud download settings for this app.” For more information on managing previous versions, see the iTunes Connect Developer Guide or contact us.
For those users who are able to update their machines to Mavericks, the new operating system is a free download available now on the Mac App Store.