DICE said they'll stop refreshing Battlefield 1 with monthly updates in June. This does not mean they are cutting support entirely - it means support will come not as often because they are shifting people to work on the next instalment.
The developers of Battlefield 1 have revealed some changes coming to the game's model in June, presumably to shift focus onto the next game in the series. If the release of They Shall Not Pass for all players is anything to go by, it isn't impossible to imagine that more maps and expansions will be added to every player's arsenal no matter their DLC purchases. Before patch notes start appearing less often, the team will release a new game mode called Shock Operations.
Recently, Rupture was added to the free map roster, which might have sparked the further release of additional maps from expansions like They Shall Not Pass. Apparently, since DICE is making the next instalment we can surmise they are shifting workers from one project to the next possibly in order to prepare for an E3 2018 reveal.
In June, Shock Operations will be coming to the game as the final part of the monthly updates the game has enjoyed for the past 18 months. The already existing Operations mode pits players against each other across multiple maps in a single skirmish. No additional changes for other game modes have been documented in the newest roadmap.
Shock Operations are essentially an evolved version of Operations where players will fight zone by zone at a time on a singular map with 40 players participating in five locations. The new game mode will be coming to all players for free, so we can all thank EA for giving us these monthly updates.
Battlefield 1 was released in 2016 for PC, Playstation 4 and Xbox One. The sequel is coming later this year according to reports, and there are rumours that it will be set in World War II, which would seem to be a logical choice for the team. The game might also have a battle royale mode, but that is still unconfirmed.