Upcomming RMW Feature Freeze - April 6th, 2026 - ROS Lyrical
The Robot Operating System will lock middleware packages for 6 weeks to stabilize its next major version.
The Open Source Robotics Foundation (OSRF) has officially triggered the feature freeze for the ROS Middleware (RMW) layer of its upcoming ROS 2 'Lyrical Luth' release. Effective April 6, 2026, all development on new features for core communication packages will halt. This freeze impacts critical middleware implementations including rmw_fastrtps (for Fast DDS), rmw_cyclonedds, rmw_connextdds, and the newer rmw_zenoh, along with their underlying vendor libraries like Fast-CDR and iceoryx. The move is a standard part of the ROS 2 release cycle, designed to stabilize the codebase for the final six-week sprint before launch.
This freeze locks the APIs and core functionality that allow different nodes in a robotic system to communicate. While new features are paused, the development team will continue to accept and integrate critical bug fixes to ensure the May 22, 2026 release is robust. Lyrical Luth is expected to be a Long-Term Support (LTS) release, meaning it will receive updates and security patches for years, making this stabilization phase crucial for the global robotics community that relies on ROS for research, prototyping, and commercial deployment.
- RMW feature freeze begins April 6, 2026, for the 'Lyrical Luth' ROS 2 release.
- Core packages affected include rmw_fastrtps, rmw_cyclonedds, rmw_zenoh, and their vendor libraries.
- Only bug fixes will be accepted until the official branch from ROS Rolling on May 22, 2026.
Why It Matters
This freeze ensures a stable, production-ready LTS release for thousands of robotics developers and companies building autonomous systems.