Found this on a Dutch blog, screenshot taken from a German folder. Reportedly an M4 convertible in Estoril Blue.
http://www.autoblog.nl/image-gallery...BMW_M4_Cabrio/
BIMMERPOST ADDENDUM:
Some sites have been reporting the above image as a leaked official photo, but as you can see below, it's simply a photoshopped image of an official wallpaper image of the 435i Convertible (
source) using styling elements from the M4 Concept. Hence the oddly angled front wheel.
The real M4 Convertible should not be much different than the photoshopped image however, as it will share exterior styling with the production M4 Coupe, which will adopt its styling from the M4 Concept.
See what the real M4 Convertible looks like in our
recent spy photos.
Have a look at our previous M4 Convertible renderings: