XML 1.0
Extensible Markup Language (XML) 1.0 is the foundational W3C Recommendation defining the syntax and processing model for XML documents. First published in 1998 and now in its Fifth Edition (2008), XML 1.0 specifies well-formedness, validity, character encoding, and the basic constructs (elements, attributes, namespaces, processing instructions, comments, and entities) that all XML technologies build upon.