Vivo V15 Pro will have its premiere next week; now it turns out that a mysterious U1 smartphone will be released before it, and as early as tomorrow too. What do we know about it? Not a lot. Judging by the teaser render, U1 will have a tear-shaped notch. People wiser than me believe that Vivo will release three variants of the device, with different prices and specs, but that is only a supposition.