Up front, the headlights are angled back slightly and no longer meet the bumper. The fender extends forward in a similar way to the 993 generation of 911s. There appears to be a faint line on the front of the car that mimics the shape of the current model, but it's all for show. Since the headlights are canted back, the fender bulge isn't as pronounced.
Around the side, the changes are minimal. The door handle is now flush with the body, but that looks to be the biggest change. The window and roof carry over the same basic shape that's been around since 1963.
Out back, the spoiler now spans the width of the car rather than ending at the edges of the hood. Porsche appears to be considering a move back to quad exhaust tips for non-Turbo models. When the 911 moved to an all-turbocharged lineup, lower trim models gained dual, center-exit exhaust. The full-width light bar means this car is likely an all-wheel drive model. The current 911 just recently received a refresh, so don't expect to see a full reveal of this car anytime soon. Look for it at an auto show come mid to late 2018 as a 2019 model.