GarageSale 6.9.3 is in the “Waiting for Review” phase of the App Store submission process. I expect it to be available on the Mac App Store late this or early next week.
You can also use GarageSale 6.9.3 from our website. It will recognize your App Store purchase and not require an additional license. However, we had at least one customer reporting data loss when hoping between version, therefore my advise is make sure you have a complete backup of your hard disk before giving this a try.