EA will continue to update Battlefield 1 up until June this year. Thereafter the game will not receive any more monthly updates and additional content.
This news comes from a recent blog post on the official Battlefield website. The post details the roadmap for Battlefield now that the last expansion, called Battlefield 1 Apocalypse, has been released. Up until June Battlefield 1 will still receive frequent updates and some additional content updates and tweaks. However, after June, there is no plan for additional updates.
This change would fall in line with EA preparing for the launch of Battlefield 5 later this year. This means that the team that worked on continuous updates would shift their focus on the upcoming game, getting ready to support it when it finally is launched.
Gamers would still be able to play Battlefield 1 though. Much like older Battlefield titles, server support for the game will continue.