XML Sources and Versions
A large part of XML comes from SGML. The only difference is that the document character set is Unicode, and it has a fixed delimeter set.
Other sources include text Encoding initiative (TEI), HTML, Extended Reference Concrete Syntax (ERCS).
The first version of XML was defined in 1998. Its fourth edition was published ion August 16, 2006. The second version (XML 1.1) was published on February4, 2004.