- Introduced many new features: task instance mutation hook, new secret backends (AWS Secrets Manager, Local Filesystem, Vault, Systems Manager), Python 3.8 support, new CLI commands (airflow info, config), SQL Branch operator, and extensi...
- Delivered a large set of bug fixes and UI improvements, including fixes for DAG serialization, RBAC UI rendering, logging, DockerOperator JSON handling, task state colors, performance regressions, and various UI tooltip and view issues.
- Added security hardenings (XSS defence, default deny for experimental API, XCom write restrictions), numerous documentation updates, deprecation warnings for duplicate task IDs, and several minor refactorings and compatibility tweaks.