Butterfly is developed on 64 bit Windows 8.1 Professional. However, it's actively tested on Windows 7, both 32 and 64 bit versions. Windows XP or Windows Vista are not supported. There will not be a Linux version of Butterfly, please don't ask about it.
I thought it was trying to be an OSS, cross platform Foobar2k until I saw the platform disclaimer. IMO Foobar solved the music player problem on Windows a good while ago.
Butterfly is developed on 64 bit Windows 8.1 Professional. However, it's actively tested on Windows 7, both 32 and 64 bit versions. Windows XP or Windows Vista are not supported. There will not be a Linux version of Butterfly, please don't ask about it.