It's still a careful evolution of the RS.18 (and even Abiteboul who's often too optimistic and quite careless in his statements says this car is cautious evolution and is less agressive that some of its competitors)
But these are the novelties I noticed, They're quite new to f1 too, I mean they are different interpretations atleast. It seems Renault did their homework more than in 2018, studied the rules more deeply and tried to find new exploitable zones. So Renault is in the right path...
-Mini bargeboards behind the bargeboards
-mini winglets on the halo feet
-upwashy rear wing strakes on the endplates
-vertical vanes below the sidepod intake
(The new Racing point too has a vertical vane under the sidepode lower lip but its way bigger and it reaches the floor)
You can find high res pics in this bulgarian? website
http://f1.f-e-n.net/index.php/url7134
RS.19 is a nice addition to my collection (cough)
Just for fun.