Saxon
XQuery Updates implementation
XML Schema 1.1 implementation
XML Schema 1.0 implementation
XSLT 2.0 implementation
XQuery 1.0 implementation
XQJ (JSR 225) interface
S9API interface
JAXP interface (transformation, XPath, schema processing)
Extensibility mechanisms
Saxon extensions to the W3C XSLT/XQuery specifications
Diagnostics and tracing
Changes specific to .NET
Internal changes
Serialization
Optimizations and performance improvements