Apple analyst, Ming-Chi Kuo, also claims that the ultra-wide-angle lens will be upgraded to ƒ/1.8 aperture.
However, he claims that only the iPhone 13 Pro models will get this upgrade. Thus, the only consistent rumor is that the iPhone 13 series will use a higher ultra-wide-angle lens.
As for the number of models to use this lens, the reports are not consistent for now. Ming-Chi Kuo also predicts that the flagship iPhone series in 2022 will retain this ultra-wide-angle lens.
A larger aperture will allow more light to pass through the lens. An aperture from ƒ/2.4 to ƒ/1.8 may significantly improve the low-light performance of the iPhone 13 model when shooting in ultra-wide-angle mode.