When you integrate your product catalog via an XML file, Insider provides two types of out-of-stock management. In the XML product catalog integration menu, you can select whether you want to send all products for updating the stock information while configuring the XML details:
You can manage it under each XML resource configuration page separately through the In Stock Products section. 
Send all products with their stock status
The toggle is initially disabled by default. If you want to use this configuration, you must provide the stock information for each product along with its item_id in the XML file. Any products not listed in the XML file will not be affected and will retain their current state after processing the file.
| Current Catalog Data | XML Content to be processed | Catalog after the XML processed |
|---|---|---|
| Product 1 - In Stock | Product 1 - In Stock | Product 1 - In Stock |
| Product 2 - In Stock | Product 2 - Out of Stock | Product 2 - Out of Stock |
| Product 3 - Out of Stock | Product 3 - Out of Stock | |
| Product 4 - Out of Stock | Product 4 - In Stock | Product 4 - In Stock |
| Product 5 - In Stock | Product 5 - In Stock |
Send only in-stock products
The XML file will only contain in-stock products when you enable the Show only In Stock Products toggle. Any products not listed in the XML file will be automatically updated as out of stock. On the other hand, if you include out-of-stock products in the XML file, they will be updated accordingly and remain out of stock, as expected.
| Current Catalog Data | XML content to be processed | Catalog after the XML processed |
|---|---|---|
| Product 1 - In Stock | Product 1 - In Stock | Product 1 - In Stock |
| Product 2 - In Stock | Product 2 - Out of Stock | Product 2 - Out of Stock |
| Product 3 - Out of Stock | Product 3 - Out of Stock | |
| Product 4 - Out of Stock | Product 4 - In Stock | Product 4 - In Stock |
| Product 5 - In Stock | Product 5 - Out of Stock |