XSD 1.1¶

XSD 1.1 is opt-in. Reading a 1.1 document as 1.0 is not an error — the specification designed the new constructs to be ignorable — so the version is a decision you make, not one inferred from the file.

PythonRust

import xsdkit

schemas = xsdkit.SchemaSet.from_file("report.xsd", version="1.1")

use xsdkit::{Diagnostics, Schemas, SchemaSetBuilder, Version};

fn load_11() -> Result<Schemas, Diagnostics> {
    SchemaSetBuilder::new()
        .version(Version::Xsd11)
        .file("report.xsd")
        .compile()
        .into_result()
}

Where a 1.1 construct is silently ignored under 1.0, you get a warning rather than nothing:

warning[XSD1104]: `xs:defaultAttributes` is an XSD 1.1 construct and is ignored
  --> report.xsd:2
  help: build with `Version::Xsd11` to process it

What turning it on gives you¶

Open content¶

A complex type can accept elements its content model never mentioned, either interleaved with the declared ones or only at the end.

<xs:complexType name="T">
  <xs:openContent mode="interleave">
    <xs:any namespace="##other" processContents="lax"/>
  </xs:openContent>
  <xs:sequence>
    <xs:element name="a" type="xs:string"/>
  </xs:sequence>
</xs:complexType>

xsd = """<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
                    xmlns:tns="urn:t" targetNamespace="urn:t"
                    elementFormDefault="qualified">
  <xs:complexType name="T">
    <xs:openContent mode="interleave">
      <xs:any namespace="##other" processContents="lax"/>
    </xs:openContent>
    <xs:sequence>
      <xs:element name="a" type="xs:string"/>
    </xs:sequence>
  </xs:complexType>
  <xs:element name="e" type="tns:T"/>
</xs:schema>"""

doc = '<e xmlns="urn:t" xmlns:o="urn:other"><a>x</a><o:extra>y</o:extra></e>'

xsdkit.SchemaSet.from_string(xsd, version="1.0").validate(doc).is_valid  # False
xsdkit.SchemaSet.from_string(xsd, version="1.1").validate(doc).is_valid  # True

xs:defaultOpenContent applies the same rule to every complex type in a document, so a schema family can be made extensible in one line.

Default attributes¶

<xs:schema defaultAttributes="tns:Common"> attaches an attribute group to every complex type in the document — the version-stamp-on-everything pattern, without repeating it on all two hundred types.

`xs:all`, relaxed¶

XSD 1.0 confines an xs:all group tightly: it may only be a complex type's whole content model or a named group's, and each member occurs at most once. 1.1 lets members repeat, lets an xs:all nest inside another at exactly one occurrence, and lets one reference a named group — provided that group is an xs:all too.

<xs:all>
  <xs:element name="tag" type="xs:string" maxOccurs="unbounded"/>
  <xs:element name="title" type="xs:string"/>
</xs:all>

Rejected under 1.0 (XSD1302); legal under 1.1. Unique Particle Attribution applies inside an xs:all in both versions: two members that could match the same element are ambiguous (XSD1304).

Relaxed Unique Particle Attribution¶

XSD 1.0 rejects a content model where a wildcard and an element could both match the same child. 1.1 keeps the model and gives the element priority.

<xs:sequence>
  <xs:element name="title" type="xs:string"/>
  <xs:any namespace="##any" processContents="lax" minOccurs="0"/>
</xs:sequence>

Ambiguous under 1.0 (XSD1304); legal under 1.1, where title wins.

Conditional inclusion¶

The vc: attributes let one document serve both versions. vc:minVersion, vc:maxVersion, vc:typeAvailable and vc:facetAvailable decide whether an element is read at all, so a schema can carry a 1.1 refinement and a 1.0 fallback side by side.

Richer wildcards¶

notNamespace — everything except the listed namespaces.
Element Declarations Consistent, checked when a document reaches it rather than when the schema is read: a wildcard may admit a name the content model also declares, and that is an error only if no value could satisfy both.
explicitTimezone — required insists a temporal value name an instant, prohibited says it is meant to be read locally.
notQName — everything except the listed names, including the special ##defined (any element declared as a global) and ##definedSibling (any element declared as a sibling in this content model).

`xs:precisionDecimal`¶

The 1.1 numeric type that remembers its precision: 1.50 and 1.5 are equal in value and distinguishable in form, which is the point of it.

schemas.type("http://www.w3.org/2001/XMLSchema", "precisionDecimal").validate("1.50")
# '1.50' — trailing zero preserved

Local target namespaces¶

targetNamespace on a local element or attribute declaration, which 1.0 does not allow.

What is not implemented¶

Two 1.1 features are read into the model and not evaluated:

Feature	Status
`xs:assert` / `xs:assertion`	Stored on the type; never checked
Conditional type assignment (`xs:alternative`)	Parsed; the alternative is never selected

Both need an XPath 2.0 subset, which is a substantial piece of work in its own right and is the next thing on the roadmap. Until then, a document that violates an assertion validates successfully.

This is the honest caveat on turning 1.1 on: everything above works, and assertions quietly do not. The conformance figures count the cases this costs.