The best answer we can still give right now is:
As soon as possible. We're close but not ready yet.
Information on the status of the native macOS version of FL Studio can be found via the latest 'Announcement' thread in our FL Studio for Mac (macOS Development Forum).
To download the latest FL Studio 12 native macOS release and view a list of current feature disparity between the Windows and Mac versions visit the Windows vs Mac FL Studio Comparison page.
Image-Line Support Team