Most Airflow 129 tutorials, answers and DAGs in the wild were written for Airflow 2. Airflow 3.0.0 (22 April 2025) was the first major release in more than four years and broke enough of that code that you need to know what moved. The current release, checked on PyPI 2,431 on 2 October 2026, is 3.3.2 (17 September 2026), with Task SDK 1.3.2; it is the version every example in this chapter ran on.