Unfortunately, with the rules that are presently in place, Witch is not sandboxable, which means that today’s release of Witch 3.9.1 is the last with any new features in the App Store—unless Apple changes their mind, which has been known to happen if enough users let them know how they feel about things (hint hint!). We fully intend to continue updating Witch with new functionality, but all such updates will only be applicable to the direct sales version.
Their direct version can recognize Mac App Store licenses, but unfortunately they are not allowed to mention in the Mac App Store description that the direct version exists. So customers who have not signed up for an e-mail list or RSS feed are likely to see the updates stop, with no explanation. It is possible to have an in-app “news” feature that displays information to the user, but Apple will reject apps that use it to mention updates or versions outside the Mac App Store.