A new listing on China's 3C certification website has revealed a new phone with model name Vivo X20Plus UD, where 'UD' suggests the presence of an 'Under Display' fingerprint sensor on the upcoming smartphone.The 'UD', claims the report, might represent the Under Display fingerprint sensor on this phone. The phone's model number is BK1124 and the listing says that it supports fast charging and 4G LTE bands.This handset is expected to accompany the previously launched Vivo X20 Plus, with similar specifications. The phone is likely to ship with the Synaptics fingerprint sensor in line with an earlier report that Vivo would become the first smartphone brand to launch a smartphone with the new Under Display fingerprint sensor. Synaptics has claimed that as many as 70 million units of these sensors will be available in the market in 2018.The Vivo X20Plus UD is likely to be a variant of the Vivo X20 Plus launched earlier. To recap, the Vivo X20 and Vivo X20 Plus feature Full View displays with an 18:9 aspect ratio, and dual camera setup on the back. The major differences between the two variants are of screen size and battery.