Based on the camouflage, it’s obvious that the grille and taillights are the two main areas that will be changed up. Styling is likely to be influenced by the Mirai fuel-cell sedan and the Toyota Prius, both of which feature angular looks.
Inside, the Corolla is likely to receive an updated infotainment system and some minor styling tweaks.
The 2017 refresh isn’t likely to affect powertrain options, although there is a chance that a new small Atkinson cycle engine will join the lineup. If that engine doesn’t appear, then expect Toyota to add it when the Corolla is redesigned in 2019.