They've changed the optics to include 13 elements instead of 11 and doubled the aspherical elements to. This 56mm is designed for higher resolution sensors, like the recently announced X-H2.
If you've watched this channel, you know I love to put some severe reps before I get critical with any of these products until let's study how this lens improves from the predecessor and the quality of images captured. Now I should mention that this is not a review. With an 85mm full-frame equivalent focal length, the new 56mm F1.2 looks to be the premium portrait lens for X-series photographers.
I owned and used this lens extensively, and in a very-dated review, I talked about how I'd love an update with weather-sealing and better focusing. The XF56mm F1.2 is a legendary lens for Fujifilm, almost as much as the original 35mm F1.4 for the X-mount.