We’ve added some basic information to a fulfillment object in the order data; this should let you know which orders are dispatched and which are delivered and their delivery method.
The deliverycollection field was poorly named, to be honest, so it’s been removed. It did previously give you an ID that was usable in the “fulfillments” endpoint. This ID can now be retrieved from the fulfillment → id field. The “fulfillments” endpoint will give you a little extra information, but it likely isn’t needed for the basics.