For instance, the following rulings were outright scrapped:
This part regulated you can only have a maximum surface area for the flaps. This is gone now.3.7.4 In the area bounded by lines between 450mm and 1000mm ahead of the front wheel centre line, 250mm and 400mm from the car centre line and between 75mm and 275mm above the reference plane, the projected area of all bodywork onto the longitudinal centre plane of the car must be no more than 20,000mm2.
These are the 2016 regulations for the footplate. Although teams still use the footplate as roughly described in the 2016 regulations , there has been quite a bit of development in that area this year.3.7.6 Ahead of the front wheel centre line and between 775mm and 825mm from the car centre line there must be bodywork with a projected area of no less than 23,000mm2 in plan view. Furthermore, when viewed from underneath, the bodywork in this area must form one continuous surface which may not be more than 100mm above the reference plane.
3.7.7 Any longitudinal vertical cross section taken through bodywork ahead of the front wheel centre line and between 775mm and 825mm from the car centre line must contain an area no greater than 15,000mm2.
Are there oppertunities to be found in there? Probably not, but looks like they do got a bit more freedom than originally told.