September 2025 monthly summary for the jenkinsci/jenkins repository focused on stability and reliability improvements in real-time WebSocket communications. This month did not introduce new user-facing features; instead it delivered a critical bug fix to address race conditions in WebSocket transport initialization, improving operational reliability for CI workflows.

In August 2025, delivered a key connectivity enhancement to Jenkins core by introducing a dedicated Computer Connectivity Status API. The change adds an isConnected method on IComputer with a concrete implementation in Computer, distinguishing temporary offline for scheduling from disconnection from the controller. Added tests covering multiple connectivity scenarios to validate behavior. This work improves reliability of node status reporting, supports safer scheduling decisions, and reduces misreporting of connectivity.

April 2025: This period focused on delivering reliable dependency updates and removing outdated migration paths to reduce technical debt, reinforcing build stability and alignment with the current Jenkins ecosystem.

2025-03 Monthly Summary: This period delivered substantive security and reliability improvements across the Jenkins ecosystem, with a focus on secure agent connections, robust testing infrastructure, and maintainable code. Major enhancements were implemented in TLS coverage for Jenkins agents, upgrades to the testing harness, and targeted stabilization of test suites, along with enhancements to SSL/TLS handling and observability in related plugins. Key deliverables include expanded TLS testing for Jenkins agents (WebSocket and TCP, including TLS CLI arguments) and replacements for deprecated tests to validate secure agent connections; upgrades to the Jenkins Test Harness and testing dependencies to improve utilities and code clarity; and significant test stability and performance improvements through test de-flaking, logging enhancements, WebClient optimizations, and faster test execution. InboundAgentRule now supports SSL/TLS certificate configuration options, including disabling certificate checks and providing a custom certificate, ensuring accurate end-to-end agent connection behavior. CloudBees folder plugin received enhanced error logging to reduce log noise while preserving full stack traces when needed. Finally, cleaning up legacy components reduced maintenance burden and aligned the codebase with current migration paths. Overall impact: improved security, faster and more reliable tests, and lower maintenance cost, enabling faster validation cycles and more predictable releases.