rumqtt-0.25.0

Rumqtt v0.25.0 Release Notes

We're excited to announce the release of Rumqtt v0.25.0! This release brings significant improvements, new features, and important bug fixes that enhance the stability and functionality of your MQTT applications.

🚀 What's New

Enhanced MQTT v5 Support

• Session Management: Added support for session_expiry_interval in MQTT v5 connections, giving you better control over session persistence
• Authentication Packets: Implemented MQTT v5 Auth packet support for enhanced authentication flows
• Connection Properties: Made DisconnectProperties struct public for better disconnect handling
• Session Resumption: Improved session resume logic to only activate when CONNACK indicates session is present

Security & Performance Improvements

• Constant-Time Password Comparison: Enhanced security by implementing constant-time password comparison in rumqttd to prevent timing attacks
• Network Performance: Added TCP no_delay configuration option for reduced latency in time-sensitive applications
• Memory Optimization: Replaced Vec with FixedBitSet for QoS 2 packet tracking, reducing memory overhead
• Network Timeout: Set default network timeout to Duration::MAX instead of zero for better connection handling

Developer Experience Enhancements

• TLS Support: Added native TLS TlsConnector support for more flexible secure connections
• Client Configuration: New set_client_id method in MqttOptions for easier client ID management
• Public APIs: Made Server public in rumqttd and exposed v5::Connection return types
• External Auth: Re-enabled public access to external authentication features

🔧 Important Bug Fixes

Connection Stability

• Fixed panic issues on connection closure
• Resolved MQTT v5 packet writing problems that prevented outgoing packets from reaching the network
• Improved event ordering in poll() method for more predictable behavior

Subscription Handling

• Filter Validation: Added proper validation for subscription filters
• Subscribe Many Fix: Resolved critical issue where subscribe_many always caused EmptySubscription errors
• Unsubscribe Support: Added LinkTx::unsubscribe functionality

Packet Processing

• Write Operations: Ensured all write operations return correct byte counts
• PubAck Filtering: Fixed filtering of unexpected PubAck packets in event loop
• Error Handling: Removed SubAck/UnsubAck/PubAck/PubRec/PubRel/PubComp reason code errors from critical state errors

📚 Code Quality & Maintenance

Dependency Updates

We've updated several critical dependencies for security and performance:

• OpenSSL: 0.10.64 → 0.10.71
• H2: 0.4.2 → 0.4.4
• Rustls: 0.22.2 → 0.22.4
• Various Go dependencies in benchmarks

Refactoring Highlights

• Simplified Network implementation with Framed<.., Codec>
• Improved credential storage using Login in MqttOptions
• Enhanced unsolicited publish handling
• Better clippy compliance and code quality

🎯 Breaking Changes

While we've maintained backward compatibility where possible, please note:

• Some internal APIs have been refactored for better performance
• Error handling has been improved, which may affect error matching in your code
• Default network timeout behavior has changed

🤝 Community Contributions

A huge thank you to our 16 new contributors who made this release possible! We're thrilled to welcome these developers to the RumQTT community:

New Contributors:

• @amokfa - Fixed write operation byte counting
• @pranavgoel29 - Added subscription filter validation
• @Inventor77 - Implemented secure password comparison
• @xiaocq2001 - Added MQTT v5 session expiry and session resume improvements
• @wangwen-4220 - Fixed PubAck filtering in event loop
• @hippalus - Optimized QoS 2 packet tracking with FixedBitSet
• @FedorSmirnov89 - Added TCP no_delay configuration option
• @silvestrpredko - Re-enabled external auth public availability
• @FSMaxB - Fixed critical subscribe_many functionality
• @J-Kappes - Improved TLS documentation
• @CosminPerRam - Fixed EventLoop documentation spelling
• @Ddystopia - Fixed default network timeout behavior
• @edgale - Fixed function description typos
• @elrafoon - Added MqttOptions set_client_id method
• @Ichmed - Made Server public in rumqttd
• @jbeyerstedt - Made v5::Connection return types public

This diverse group of contributors brought improvements ranging from security enhancements and performance optimizations to API improvements and documentation fixes. Their combined efforts have made RumQTT more robust, secure, and user-friendly.

Special recognition goes to contributors who tackled complex issues like MQTT v5 protocol implementation, security vulnerabilities, and critical subscription handling bugs.

🔄 Migration Guide

For most users, upgrading should be straightforward:

1. Update your dependency: Change your Cargo.toml to use rumqttc = "0.25.0"
2. Review timeout handling: If you rely on specific timeout behavior, review the new default timeout settings
3. Check error handling: Update any code that specifically catches the removed reason code errors
4. Test MQTT v5 features: If using MQTT v5, test the improved session handling and auth features

🔗 Resources

• Full Changelog: View on
• Documentation: Check our updated docs for new features and API changes
• Issues: Report bugs or request features on our GitHub repository

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This release represents months of community effort and testing. We're confident it will provide a more stable, secure, and feature-rich MQTT experience for your applications.

Happy coding! 🦀