The Wunderlist / To Do team in a blog post announced that the legacy app will go dark on May 6, 2020. With having spent so much time and effort to get the To Do app up to speed, Wunderlist hasn’t received the infusion of new features and updates it used to enjoy. As it ages and as new technology emerges, they can no longer guarantee that it will continue to work as it should. Thus, it needs to be retired.