The manga began in 2015 and has thirteen volumes out as of May 2019 and according to the latest Weekly Shonen Magazine, the final arc is getting underway.
It’s unclear how long this particular arc will run but it’s expected to wrap up this year based on previous arc material.
With an anime adaptation of the Boarding School Juliet manga from Yosuke Kaneda out last fall, the manga itself is now getting ready to enter its final arc.