China Patent Office has posted patent images of the upcoming BMW 4-Series Cabrio (Convertible) that make it abundantly clear what the production model looks like.
The retractable soft top makes the car much lighter than a hardtop would be while giving it more trunk space.
As for the specification, our best guess is 430i: the 440i normally has different exhaust tips, while the М Perfomance has large front air intakes missing on the pictures.
The cabin remains to be revealed, but it would be logical to assume it will look identical to the coupe version (see video).