The Future of Deliveries on the Deliveries blog:
It’s likely that over time, more services in Deliveries will no longer show tracking information directly in the app. You won’t see the delivery date, the map route, or any of the details, and you won’t get notifications about changes to the status. You will need to use the “View Online” button to see your tracking information on the shipping company’s web site.
I recently moved into a new house and as you can imagine, I'm getting a lot of deliveries right now, and the Deliveries app would traditionally be super useful in tracking my orders across multiple providers in once place. As you can see in the screenshot at the top of this post, its usefulness is severely cut down by FedEx's refusal to work with Deliveries anymore.
I can't imagine Deliveries was doing anything nefarious, although I guess I'd be curious to hear from FedEx and Amazon why they revoked API access to the app. I suspect I'd be unimpressed with their "we think the best way for customers to track their packages is from our app" answer, though.
Anyway, I have switched over to Parcel for now, although I really don't like its UI as much as Deliveries, but given it seems to still work with the shipping companies I tend to use, it's functional…for now. If this is part of shipping companies revoking API access from well-behaved devs, maybe their days are numbered as well.