The International Maritime Organisation  has set the global sulphur ban to begin on 1 January 2020 but there are suggestions and concerns it could be fast-tracked in one way or another. It could be as early as 1 Jan 2019, so lines really need to think about how they are going to comply.

https://www.porttechnology.org/news/imo_continues_to_push_through_sulphur_ban