#Version 1.1.0 (March 2026)

Major update focused on standards compliance, streaming, and API completeness.

#XSLT Engine

  • Streaming execution: XmlReader-based forward-only processing for xsl:source-document streamable="yes" and xsl:mode streamable="yes"

  • Stream API: TransformAsync(TextReader), TransformAsync(Stream), TransformAsync(TextWriter), TransformAsync(Stream, Stream), ResultDocumentHandler

  • Serialization: indent="yes" (XML, HTML, XHTML), DOCTYPE generation, suppress-indentation, byte-order-mark, escape-uri-attributes

  • xsl:record: Proper XDM map construction

  • xsl:expose: Full package visibility control (conformance tests enabled)

  • Error handling: Proper XTSE0020 for invalid on-no-match/on-multiple-match values

  • System properties: supports-streaming=yes, supports-namespace-axis=yes, xpath-version=4.0

#XQuery Engine

  • Direct element constructors: <element>text {expr}</element> with ANTLR lexer modes

  • XQuery Update Facility: Full execution (insert, delete, replace, rename, transform copy-modify-return)

  • Annotations: %public, %private, %updating on function/variable declarations

  • String constructors: [Hello {$name}!] backtick interpolation

  • Module imports: Parsed with XQST0059 error when resolver not configured

  • UCA collations: Unicode Collation Algorithm with lang/strength/fallback parameters

  • External variables: SetExternalVariable() API with XPDY0002 for unbound

  • JSON serialization: Maps/arrays serialize as JSON, declare option output:method "json" support

  • Node constructors: All constructor types (element, attribute, text, comment, PI, document) fully operational

#CLI Tools

  • xslt CLI: --stream flag for large file processing, version 1.1.0

  • xquery CLI: --output json flag, auto-detect serialization options, version 1.1.0

  • CLI tools moved into engine repos (same CI, same release)

#Quality

  • 843 XQuery tests (including 30 integration tests through XQueryFacade)

  • 300 XSLT tests (including 36 integration tests through XsltTransformer)

  • Zero TODOs in source

  • Zero silent exception swallowing

  • All README claims verified by tests

#Version 1.0.0

Release Date: 2025

The initial release of PhoenixmlDb, a modern embedded XML/JSON document database for .NET.

#Features

#Core Database

  • Embedded database with LMDB storage

  • ACID transactions with MVCC

  • Multiple containers per database

  • XML and JSON document storage

  • Document metadata support

#Query Engine

  • Full XQuery 3.1 implementation

  • XQuery 4.0 features (partial)

  • XPath 3.1 support

  • XSLT 3.0/4.0 transformations

  • Query optimization

  • Prepared queries

#Indexing

  • Path indexes for element/attribute lookup

  • Value indexes for range queries

  • Full-text indexes with stemming

  • Structural indexes for navigation

  • Metadata indexes

#Server Mode

  • gRPC-based server

  • TLS support

  • Authentication (basic, API keys)

  • Role-based access control

  • Health monitoring

#Cluster Mode

  • Raft consensus for leader election

  • Automatic failover

  • Sharding with consistent hashing

  • Replication for fault tolerance

  • Distributed transactions (2PC)

#System Requirements

  • .NET 10.0 or later

  • Windows 10+, Linux (Ubuntu 20.04+, RHEL 8+), macOS 12+

#Known Limitations

  • XQuery full-text extension not yet implemented

  • Schema validation is basic (planned for 1.1)

  • XSLT streaming limited to certain patterns

  • Maximum database size limited by LMDB (depends on platform)

#Upgrade Notes

This is the initial release. No upgrade path needed.

#Roadmap

#Version 1.2 (Planned)

  • Full XML Schema validation

  • XQuery Full-Text extension

  • Improved query optimizer

  • GraphQL API

  • More XSLT 4.0 features

#Version 1.3 (Planned)

  • Change data capture (CDC)

  • Event sourcing support

  • Improved cluster rebalancing

  • Admin UI

#Future

  • Geographic replication

  • Column-oriented storage for analytics

  • Machine learning integration

  • Cloud-native deployment options

#Deprecation Policy

  • Major versions supported for 3 years

  • Minor versions supported for 1 year

  • Security patches for supported versions

  • Migration guides provided for breaking changes

#Contributing

We welcome contributions! See our Contributing Guide for details.

#License

PhoenixmlDb is licensed under the Apache 2.0 License.

#Acknowledgments

PhoenixmlDb builds on these excellent projects:

Special thanks to the W3C for the XQuery, XPath, XSLT, and XDM specifications.