Since Mercedes didn't even bother to properly disguise the prototypes, it looks like the design changes will be subtle.

There’s certainly no shortage of spy content with the mid-cycle refresh Mercedes is preparing for the entire C-Class family and today we are able to bring a video showing the two-door versions. Both were spotted undergoing final testing and had only very little camouflage, thus suggesting the styling changes on the outside are going to be discreet.

Update:

The biggest novelty will be the implementation of two different types of LED headlights and it will be interesting to see whether the cheapest C-Class will continue to have an old-school halogen setup in certain markets. Both the coupe and convertible spotted here in Germany had the optional Multibeam LED setup derived from the E-Class and only carried camouflage on the front bumper.

Chances are the test vehicle did not have all the final bits and bobs in place as we’re expecting a slightly modified rear bumper as well as a new look for the taillights, though nothing to write home about. New alloy wheel designs and possibly fresh body paint choices will round off the changes on the outside.

The real magic will occur inside the cabin where the entire C-Class family will receive a fully digital optional instrument cluster, a wider infotainment screen, and a new touchpad. Seen already in the GLC F-Cell, the new setup looks better than the current configuration, but we’re sure some would have hoped to see the fancier dual digital display of the more expensive Mercs, especially since even the entry-level A-Class in its next iteration will have a similar setup.

According to Auto Motor und Sport, the whole C-Class lineup will be refreshed in July 2018, though online reveals of all the body styles could take place sooner than that. Further down the line, the C63 coupe might receive the hardcore R treatment bringing more power and less weight. Set to go up against the BMW M4 GTS, the C63 R will allegedly be offered as a sedan as well.

Note: Spy photos below are showing a different prototype of the coupe.

Mercedes C-Class Coupe facelift spy photos