From PetaPixel:
Xiaomi has announced that it�s upcoming 12S Ultra will use the full size of Sony�s IMX989 1-inch sensor. The phone, which is also co-developed with Leica, will be announced on July 4.
Xiaomi�s Lei Jun says that the 1-inch sensor that is coming to the 12S Ultra, crucially, won�t be cropped. How the company plans to deal with physical issues Sony came up against in its phone isn�t clear. Jun also says that Xiaomi didn�t just buy the sensor, but that it was co-developed between the two companies with a total investment cost of $15 million split evenly between them. The fruits of this development will first come to the 12S Ultra before being made available to other smartphone manufacturers, so it�s not exclusive to Xiaomi forever.
... only the 12S Ultra will feature a 1-inch sensor while the 12S and 12S Pro will feature the Sony IMX707 instead.