We’ll keep this short tonight. As of 11:30PM Eastern, whenever you create or edit an inbound shipment, the expected quantities for the affected inventory locations will automatically update to reflect all open inbound shipments. You will receive a skuInventoryChange callback once totals are calculated for each affected sku. The total_available_to_sell and total_unit counts will not change because units have not been received yet.
There are no API changes, just an under the hood change to ensure inventory accuracy.