I love Steins; Gate OST 'Farewell' very much. I listen to the music again and again.
But I notice that There is another version of 'Farewell'. (It's not Suzuha.) The music was used in episode 21, when Okabe told Kurisu her death in Beta worldline. The music is different from original 'Farewell', it's more sad.
Where can I find the music? Is it official release?