Negative stock is no longer possible
Until now stock could go negative in some situations, for example when you created an order manually in the back end of your webshop while stock was already at 0.
That is a thing of the past. When a product has no stock left, a new order is automatically set to backorder, whether you have the backorder option switched on or off.
As soon as you add stock for that product again, the order automatically changes from backorder to open. That way your stock stays accurate and you prevent incorrect shipments.