And so is Ys 3 currently too. PCE version as well.
This is kind of redundant; every game on the Japanese PSN store that predates the original PlayStation is a PCE game. Still not sure why it has a PCE section to begin with, but I'm not complaining (well, except for Popful Mail not being on there; c'mon, Falcom and Sony, you know you wanna add it).
Falcom games cleared: Ys I & II Chronicles, Ys: The Oath In Felghana (PSP), Ys: Memories of Celceta, Ys VI: The Ark Of Napishtim (PC), Ys Seven, Ys Origin, Trails In The Sky FC (PSP, PC), Sora no Kiseki SC (PSP), Sora no Kiseki the 3rd (PSP), Zero no Kiseki Evolution, Ao no Kiseki Evolution, Sen no Kiseki (PS3), Sen no Kiseki II (PS3, Vita)
Still playing: Popful Mail (PC Engine CD, Sega CD)
Waiting on: Trails In The Sky SC (PC), Ys V remake, Ys VIII/Eight