Up front, the M4 sports new headlight internals, while the front splitter is much more prominent than the one fitted to the today's standard car.
At the back, the M4 will feature revised tail-light design that look to be the same OLED units featured with the GTS - the same model that donated this prototype's wheels.
The spy photographers also managed to snag a photo of the high-performance coupe's interior, where covers have been liberally deployed across the dashboard, suggesting that there might be a number of updates in store.
It's expected that the revised M4 will carry on with the current car's drivetrain, which features a 3.0-litre twin-turbo straight-six pumping out 317kW of power and 550Nm of torque to the rear wheels.
When paired with the seven-speed dual-clutch transmission, the current M4 is good for a 0-100km/h time of 4.1 seconds.
The refreshed 4 Series range - what BMW calls an 'LCI' or 'Life Cycle Impulse' - is likely to hit Australia around the middle of next year, but this revised M4 may not arrive until later. Watch CarAdvice for more on both coming updates.