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.
The App Store team
This functionality was recently added to iOS apps as well.