This chapter reminded me why I love this series...
Sensei has announced at the end of volume 5 (chapter 25.5, coming soon™) that the story of "Kimi to Tsuzuru Utakata" will conclude in 6 volumes.
She later mentioned on her
FANBOX that it was her own decision to conclude the story in the next volume, after discussing it with her editor. There's no external pressure, it's the author's intention.
She also said that she'll do her best to bring the story to the conclusion, but there might be times when she will have to take a hiatus. She hopes that we'll continue to support her until the end.