This test car has camouflage taped around the front, but the outline of the new grille is still visible. Like the Mirai, it flares downward from the top, and there are big gills at each corner. Toyota's designers also reshape the headlights to give them a smoother appearance. The company masks the taillights heavily on this Corolla, which suggests tweaks to their shape, too.
You can expect Toyota to accompany the exterior updates with some interior refinements and possibly improved tech. It's not yet clear whether powertrain tweaks will be forthcoming. However, we should have a better idea in the coming months because the refreshed Corolla would likely arrive this summer.