German AutoBild claims that Red Bull might use some sort of flexible Diffusor.
(source)
TV-Footage showed the rear seemingly moving horizontally and vertically. The head of a team told ABMS: "The diffusor is basically waving. But it doesn't have to be illegal."
I gotta admit that the fact that they're not naming the person who supposedly said that, nor the team this person works for, doesn't make the claim sound really serious; but does anyone here happen to know what footage the article refers to? I haven't found anything so far.
If you no longer go for the space someone always has to leave, you're no longer a racing driver