We have heard back from Roon Labs that the temporary visibility of Marantz/Denon in the app under Roon Ready was due to development testing. This happens from time to time, and occasionally, it’s possible to even activate a device and get a brief taste of Roon Ready functionality.
Aside from that, nothing has changed in regard to announcements, promises, and timelines for certification.
It is not possible to state when a certification testing will be completed, or indeed whether a situation is reached where both parties (Roon Labs and their Partner) will conclude that testing will end and a device will not become Roon Ready.