"Never," as in "probably not."
Last February, the BMW M2's chief engineer, Frank Isenberg, told Australia's CarAdvice that "convertibles are not for racetracks, they're for cruising," in reference to the possibility of a BMW M2 convertible. He further added that "There will not be an M2 convertible. We need to keep it as purist as we did the 1 Series M Coupe." But according to Autoblog.nl, Isenberg and crew have apparently had a change of heart. Autoblog.nl claims the images you're looking at are the M2 convertible, which has yet to be announced.
Now, this seems rather strange because Isenberg also specifically pointed out the M235i convertible as the go-to drop top for those wanting nice performance and cruising fun. Was Isenberg flat-out not telling the truth or did BMW simply change its mind? After all, there are the M4 and M6 convertibles but, then again, the M2 coupe is a bit more purist-oriented than the former pair. Slicing off the M2's roof is not a challenge for engineers, but we're not convinced there's even a market for this car. Just because the M2 coupe is a hit doesn't necessarily mean a convertible variant will match that success. When could this M2 convertible be revealed (if at all)? Paris or Geneva are a couple of good bets.