The "Sell from all locations to all shipping zones" option of fulfillable inventory is being removed. All shops will use the "Sell only within configured shipping zones" option.
This change helps prevent overselling and reduces situations such as canceled orders due to stock unavailability for their region, or manual intervention to correct orders.
What this means: At checkout, customers can only complete purchases for products that are in stock at a fulfillment location that is configured to deliver to their shipping zone. If an item is unavailable at all locations for the customer's shipping zone, then they can't purchase that item at checkout and will see delivery or stock related errors.
This behaviour has already been enabled automatically for most shops. If your store hasn't been migrated yet, we've notified you directly and the change takes effect on September 30th.
Learn more about fulfillable inventory and how to prepare for the change.