Today there was a Harmony fanclub announcement, that one of the Kalafina members has decided to quit the band. There is still no menthion on who it is, but they say it ll be announced soon.
Additionally on at the Japanese Platform for Patent information, (under “Retrieval keyword” enter “Kalafina” > “search”, > “Search results: 1” and then click on “View List”, click Appl.No.2017-170294 to get the details.) there can be found an application for the “Kalafina” trademark ownership, applied by Keiko Kubota, on December 28, 2017, but we dont know what this could possibly mean.
info: yuki.n, HimeWakana, Kugayama
Update: This paper says it will be Keiko the one who quits! But we will still have to wait for official confirmation.