When you update the files for a specific variant you may want to notify all previous customers. This can also be used for pre-orders of a product where you attach the files after the initial purchase and then notify all customers that their files are ready.
Select your product and product variant
Update files/videos for a given product
Click "Notify All Past Customers"
Preview and edit the email. Once you are ready to send to all past purchasers click "Send"
This will notify all previous customers who purchased this item while Sky Pilot was installed in your Shopify store.