xetex was initially released for mac os x only in april 2004 with built-in aat and unicode support. in 2005 support for opentype layout features was first introduced. during bachotex 2006 a version for linux was announced, which was ported to microsoft windows by akira kakuto a few months later, and finally included into tex live 2007 for all major platforms. xetex is also shipped with lyx since version 2.0 and miktex since version 2.7.