For the 2021 model year Ford did a redesign on the F150 pickup. There were also some suspension changes, mainly in the front. The knuckles have been changed and new part numbers are being released. On the 2wd trucks the struts have remained the same from the 2015-20 models but on the 4wd F150 the struts have been changed and there are new part numbers available.
In the rear there have been enough changes that there are several new flip kits available ranging from a 4 inch drop all the way down to a 7.5 inch slam.
