Version of the Tag Set (DTD)
Version of the NISO STS Tag Set that should be used to validate this standards document.
Best Practice: This attribute should be set on every document instance explicitly, even when using the XSD or RNG version of NISO STS. This is a “fixed” attribute (meaning that the value is set via a parameter entity in the DTD; thus, an author or editor cannot change it). To keep with the latest DTD, the value should be changed every time the NISO STS Tag Set changes its version number.