Changes

[http://scripts.sil.org/xetex XeTeX] is a new TeX engine by Jonathan Kew and SIL International, which combines eTeX with pervasive [http://en.wikipedia.org/wiki/Unicode Unicode] support and advanced font support (multiple language, special AAT and OpenType font features, trivial font installation). It does this by leveraging [http://developer.apple.com/fonts/ Apple Advanced Typography] support on MacOSX, so it gains its strength in features by sacrificing TeX's usual cross-platformness, and some backwards compatibility.

; PDF Literals : Because XeTeX relies on Apple's APIs to create PDFs, it is unable to take advantage of specials and other features that use native (literal) PDF commands.