These new photos of the refreshed M-Class clearly reveal a charging port in the rear bumper like its brand siblings, but the bigger question is the drivetrain underneath. At this point, it's not known whether the M-Class hybrid will share the rumored four-cylinder powertrain with the C-Class PHEV that is also testing or the S500 Plug-in Hybrid with its turbocharged, 3.0-liter V6 and an electric motor.
Being a refresh rather than an all-new model, the M-Class' styling receives only a few apparent tweaks. The front end is heavily camouflaged here, but there appears to be some changes to the shape of the headlights. At the rear, the exhaust layout has been modified, and the taillights have their backup lamps at the bottom, rather than in the middle.
All of these changes are rumored to be introduced sometime in 2015. Check out the gallery to see what you think until then.