Marini has often pointed out that one of the problems with the RC213V is aerodynamics. In Japan they have been listening to him and they brought an evolution of the fairing for their bike. The first to use it was Johann Zarco, then Luca also took to the track with the same configuration as the Frenchman.
The sides have been completely redesigned, starting with the side wings, which no longer close over the fairing, but continue downward and then extend horizontally over the 'step'. A solution that is certainly not unprecedented.
As to whether a real step forward has been taken we will have to wait for the riders' comments.