These two new features are not official yet, but first-time users can now test the latest features of Google Duo. Our US colleagues from Androidpolice are more or less the same, one of their tipsters has access to the new group calls. As of now, a maximum of seven users are permitted in a group, who must first be added to the group. During the call, no further users can be added, at least according to current status. Presumably, that still changes.
Night mode helps in dark surroundings
Google relies on the in-house software for a poor exposure. In the so-called Lowlight mode, the video image is automatically improved if you are in a rather dark environment. The software should completely detect itself if the new mode could help and suggest the activation. Google proves with its own camera app, how much your own software in Lowlight can get out.
So far it is not known when the new features for the Duo App will appear. Some patience seems necessary, at present, a small test run seems to be in progress.