It was rumored before but right now it seems to be back on. According to EW and JoBlo.com, Daniel Waters and Winona Ryder are preparing a sequel to the cult movie from 1989. Here's the info from JoBlo:
According to the "Deal Report" in the latest issue of Entertainment Weekly, Winona Ryder and writer/director Daniel Waters are cooking up a sequel to HEATHERS, that dark gem released during the otherwise neon year of 1989. Says Winona, "There's Heathers in the real world! We have to keep going!" That makes it sound as though HEATHERS 2 might follow her Veronica character into a work setting but, at this point, it's also possible that the film would remain in the high school milieu. If that's the case, Ryder might not have a starring role herself. How would you like your HEATHERS sequel, if at all? Waters and Ryder are currently collaborating on the dark comedy SEX AND DEATH 101, on which shooting just wrapped last week. That film will likely be released next year.