Advanced PreOrder is a Shopify app that helps store owners accept orders even when products are out of stock. It replaces the “Add to Cart” button with a “Pre-order” option, allowing customers to place orders in advance. The app also supports partial payments, so customers can pay a small amount first and complete the payment later. It includes features like “Notify Me” alerts, coming soon labels, and sales tracking. With easy setup and flexible options, it helps businesses avoid lost sales and improve customer experience.