The ones they are currently using in Africa are normal drone planes. They drop their payload without stopping though, so the payload has to be packed securely and nothing that can break easily. So it's used for medical supplies. This what Mark Rober's video was about.

If they were to create a drone that can deliver arbitrary packages, then it needs to be able to lower a package safely. That's what those renders are, they show a typical multi-rotar drone with small wings. So it can stop and lower a package. I don't think there's any real footage of these yet.

He shows the proposed new model in that video too though, not just the drone planes.

The concept of a fixed-wing VTOL UAS is well-tested, though. They’re not as simple as a quad or a “native” fixed-wing, but well within reach of a motivated hobbyist.