Vivo X20 Plus UD version got certified
New version of the X20 model got a 3C certificate in China, and this is the Vivo X20 Plus UD. Vivo has already announced that it will be the first brand to announce the phone with a fingerprint sensor under the screen so it is very possible that in this case it is just about one such model.
It is speculated that Vivo should publish such model on CES in Las Vegas, which will take place from 9-12. January 2018. It means that we will soon see what this is actually about, and the "UD" tag irresistibly resembles the "Under Display" fingerprint reader.
However, nothing has been officially confirmed at this moment because UD can mean anything else, so we will have to wait for an event that will reveal more details.