Xiaomi's sub-brand Redmi is all set to unveil the Redmi K20 on May 28, and as we inch closer to its announcement, the company revealed another one of its key selling points. Redmi has already confirmed that the K20 will come with a 48MP primary camera, 960 FPS slow-mo video recording, and a 4,000 mAh battery and today it adds the seventh-gen optical in-display fingerprint reader to the list. Redmi says that this fingerprint scanner is equipped with a 3P lens and has 7.2μm ultra-large pixels. It has a 100% higher photo-sensitive area and 30% more accuracy than the previous...