Once the changes are published, a default "No in-store stock, but more can be shipped promptly" message is displayed and the product will be available for ordering even it goes out of stock.
The stock deduction is done based on ordered quantity. When the stock level reaches 0, back order quantity is accumulated as negative stock.
Follow the below steps to change the default "No in-store stock, but more can be shipped promptly" display message.
1. Click Setup under Shopping
2. Click on the "Product Page Options" link in the other setup options:
3. Enter the new display message for "Backorder Message":
4. Save Changes