From Bikeradar
In keeping with current-generation caliper and brake pads, the new M8000 brakes receive a new lever and ‘integrated’ master cylinder design – to achieve a sleeker look, lower weight, improved durability and greater handlebar space, according to Shimano. Lever feel and feedback is said to have improved too.
Where XT was previously available in either ‘Race’ or ‘Trail’ options, Shimano has simplified the choice and now only offers a Servo Wave model, like the previous Trail versions. As previously found on the Trail brakes, tool-free reach and Free Stroke adjustment remain.
A narrower clamp band (I-Spec II compatible) offers increased adjustment – beneficial for those using remote levers for suspension and/or dropper seat posts.
Here’s another quote
The ever popular XT disk brakes have also been revised, with the new DEORE XT 8000’s featuring a lighter, cleaner and more durable integrated master cylinder, freeing up more space on the bar and giving a cleaner look. Shimano have also made some changes to the servo wave to provide more feel and feedback.