The initial version of this new wing (drawing above) was introduced in Austin and retained for Mexico by both Vettel and team mate Kimi Raikkonen. It has an extra splitter on the bottom of the endplate at the front (lower red arrow). The other difference is the additional splitter on top at the rear of the endplate (upper red arrow), designed to improve the acceleration of airflow around the outside (blue arrows) relative to the previous, single-splitter version (drawing below).
Cooling is, of course, another key consideration in Mexico due to the low air density at the high-altitude circuit. The drawing below shows the details of the manifold that Ferrari used to take air from the two outer ‘ears’ on the car’s airbox and feed it towards the engine at the rear, boosting the cooling performance of the intercooler.