1) Four rows of action buttons instead of three seen in latest preview build 12498.
2) New Flashlight & Quick Note toggles in the action center.
3) Cellular Data toggle is back. Battery Sense (?) is also present as a new quick action button.
3) Notifications appear slightly different in action center. To check how notifications appear in the current build, check below screenshot.
Thanks Rihan for the tip.Cheers!!