I do hope you implement the ability for the app to recognize that an item ihas been delivered, but marking it as complete would be a big problem, at least for me.
I live and work in buildings where deliveries are accepted by the front desk and outgoing packages/envelopes are left at the front desk for pickup by UPS/FedEx/USPS. When delivered, they are then supposed to register them in an intranet system and subsequently are either handed to us or brought up to the apt/office. Occasionally deliveries are misplaced, assigned to a wrong apartment/office, or for one reason or another not put into the intranet system. I need to see that items have been delivered to make sure I end up receiving them.
I have the app sort items by delivery time. There's no indication of category since most items were added through forwarding an email. This is the easiest way to keep track of what I should be expecting (incoming) or responses I should be getting (outgoing.) Other than reading the status, I'm not sure how else to know what's been delivered.
Changing the background color would make checking the app and knowing what needs action (items that have been delivered or items that have been delayed, as I mentioned in another post,) fast and easy.
Perhaps you could implement a horizontal swipe to archive an item, which would make archiving fast as well and maybe reduce the need/desire to have items automatically archived. I don't know many people who wouldn't want to see their shipment has been delivered, especially if archiving was as easy as a swipe vs. having to select an item, hit menu and then hit mark as completed.
Thanks. Hope I've made sense.