This article discusses two useful features of XML Schema 1.1: "Co-occurrence constraints", and "Conditional Type Assignment".

Tim Bray on XML's 20th birthday

Peter Krautzberger discusses strategies for representing mathematical equations in XML and on the web.

B. Tommie Usdin, one of the developers of NISO STS, introduces us to the new standard for the XML interchange of standards

OASIS Genericode is a standard developed for interchanging code lists in XML. Here, Ken Holman discusses an unanticipated but useful application of Genericode to tables that are not entirely full of content and not in any way related to code lists.

Although it's tempting to use the same technology wherever possible, it does not always lead to the best results. Ken Holman discusses some differences between XML and JSON and when to use each, prompted by a discussion on the XML-dev mailing list.

Topic maps is a way of organizing information that is seldom in the news these days. One of the foremost practitioners describes topic maps, the relationship to some other technologies, and his assessment of the current status.

Peer-to-peer blockchain users have long accepted (or leveraged in the case of drug dealers and ransom seekers) the anonymity provided in transactions and the lack of a paper trail. Blockchain users are increasingly seeking to use the blockchain for legal business trading, meeting their obligations for documenting the procurement and transportation steps of a transaction. UBL provides the means to do so in an internationally-standardized XML document vocabulary.

The XML specification has many complex areas, largely for historical reasons, and the widely used XML Namespaces specification compounds the complexity. There has always been interest in simplifying XML at its bedrock layer, and a community group created MicroXML, a specification that reduces XML, entirely specified, to around 8 pages even while adding a data model, which is not part of XML 1.0. MicroXML is backwards compatible yet far simpler and more secure than XML 1.0, introduced in this second article of the Simplifying XML series.

Adding a lightweight Relax NG schema on top of an unmodified base schema offers an advantage that Schematron constraints cannot provide: Content completion.