The FIA has shown a green light to Mercedes’ controversial new mirror design.
The reigning champions brought a substantial upgrade package to Austria, and the aerodynamically-styled mountings of the mirrors attracted attention in the pitlane.
"This is illegal," Ferrari technical boss Mattia Binotto is quoted by Auto Bild.
FIA technology boss Jo Bauer added: "Let’s wait, but they can drive how they like in free practice."
Certainly the Mercedes drivers seemed to like the Austria update.
"From the moment I drove out of the garage, the car felt better than it did last week," said Lewis Hamilton.
And Italian newspaper Corriere della Sera said the FIA ultimately decided that Mercedes can keep using the controversial new mirrors in qualifying and the race.
"Everything seems to work so far," team boss Toto Wolff told Bild newspaper.
"But we still have to wait for qualifying and the race. I can imagine that the top three in qualifying will be hundredths of a second apart."