Back in Stock Notification module allows your customers to subscribe for Out of Stock Nulled products and get notified as soon as it appears in the warehouse.
What if a stock runs out of a particular product? Via Out of Stock Subscription module, the customers will be able to subscribe to this product and receive a notification as soon as it appears in the warehouse, and you will have a complete understanding of the demand for all products.
Also, you can use Back in Stock Notification module as a tester of new products.
Allow your customers to subscribe for out of stock products and collect information how many customers would like to buy it before you’ll have it in stock.
Demo : https://addons.prestashop.com/en/emails-notifications/20091-out-of-stock-subscription-back-in-stock-notification.html