Popular mid-sizer is due for a generational overhaul in the near future, and it looks to be an evolution, not revolution, of the current model.

A prototype believed to be the next-generation Mercedes-Benz C-Class has been snapped during cold weather testing on the snowy roads of Europe this week.

Despite the heavy black-and-white camouflage, we can see the new C-Class will be an evolution of the current model in terms of its overall shape, though finer details like the front and rear fascias are too concealed to get a firm idea of the final design.

Photographers noted a new position for the plug-in hybrid version's charging port (below), which can be seen on the left side of the rear fender on this vehicle, instead of the rear bumper like on the current model.

It's believed the next-gen C-Class will stay around the same size as the current model, based on a revised version of the MRA2 rear-drive architecture that underpins the version on sale today.

The plug-in hybrid powertrain believed to be powering the vehicle shown here will be offered alongside a range of more conventional offerings, including four- and six-cylinder turbocharged petrol and diesel engines that will likely draw upon the company's EQ Boost 48V mild-hybrid technology.

Other upgrades include the company's new MBUX infotainment systems, enhanced semi-autonomous driving capabilities, and improved space for passengers and luggage.

As for timing, we're expecting the new C-Class to be revealed sometime in 2020 ahead of a 2021 market launch, meaning it's still some time away.

Sedan and wagon versions are expected to carry over, and there's scuttlebutt surrounding an All-Terrain wagon version as well. Additionally, the high-performance AMG versions will live on, likely augmented with mild-hybrid technology for the first time.

Beyond the core range, it's likely the popular coupe and cabriolet versions will surface six to 12 months after the sedan and wagon.

Stay tuned to CarAdvice for all the latest, and click on the images for the full gallery.