Bug Fixes

• Bugfix: TypeError when Serializing & sorting iterable properties of DAGs (#15395)
• Fix missing on_load trigger for folder-based plugins (#15208)
• kubernetes cleanup-pods subcommand will only clean up Airflow-created Pods (#15204)
• Fix password masking in CLI action_logging (#15143)
• Fix url generation for TriggerDagRunOperatorLink (#14990)
• Restore base lineage backend (#14146)
• Unable to trigger backfill or manual jobs with Kubernetes executor. (#14160)
• Bugfix: Task docs are not shown in the Task Instance Detail View (#15191)
• Bugfix: Fix overriding pod_template_file in KubernetesExecutor (#15197)
• Bugfix: resources in executor_config breaks Graph View in UI (#15199)
• Fix celery executor bug trying to call len on map (#14883)
• Fix bug in airflow.stats timing that broke dogstatsd mode (#15132)
• Avoid scheduler/parser manager deadlock by using non-blocking IO (#15112)
• Re-introduce dagrun.schedule_delay metric (#15105)
• Compare string values, not if strings are the same object in Kube executor(#14942)
• Pass queue to BaseExecutor.execute_async like in airflow 1.10 (#14861)
• Scheduler: Remove TIs from starved pools from the critical path. (#14476)
• Remove extra/needless deprecation warnings from airflow.contrib module (#15065)
• Fix support for long dag_id and task_id in KubernetesExecutor (#14703)
• Sort lists, sets and tuples in Serialized DAGs (#14909)
• Simplify cleaning string passed to origin param (#14738) (#14905)
• Fix error when running tasks with Sentry integration enabled. (#13929)
• Webserver: Sanitize string passed to origin param (#14738)
• Fix losing duration < 1 secs in tree (#13537)
• Pin SQLAlchemy to <1.4 due to breakage of sqlalchemy-utils (#14812)
• Fix KubernetesExecutor issue with deleted pending pods (#14810)
• Default to Celery Task model when backend model does not exist (#14612)
• Bugfix: Plugins endpoint was unauthenticated (#14570)
• BugFix: fix DAG doc display (especially for TaskFlow DAGs) (#14564)
• BugFix: TypeError in airflow.kubernetes.pod_launcher's monitor_pod (#14513)
• Bugfix: Fix wrong output of tags and owners in dag detail API endpoint (#14490)
• Fix logging error with task error when JSON logging is enabled (#14456)
• Fix statsd metrics not sending when using daemon mode (#14454)
• Gracefully handle missing start_date and end_date for DagRun (#14452)
• BugFix: Serialize max_retry_delay as a timedelta (#14436)
• Fix crash when user clicks on "Task Instance Details" caused by start_date being None (#14416)
• BugFix: Fix TaskInstance API call fails if a task is removed from running DAG (#14381)
• Scheduler should not fail when invalid executor_config is passed (#14323)
• Fix bug allowing task instances to survive when dagrun_timeout is exceeded (#14321)
• Fix bug where DAG timezone was not always shown correctly in UI tooltips (#14204)
• Use Lax for cookie_samesite when empty string is passed (#14183)
• [AIRFLOW-6076] fix dag.cli() KeyError (#13647)
• Fix running child tasks in a subdag after clearing a successful subdag (#14776)

Improvements

• Remove unused JS packages causing false security alerts (#15383)
• Change default of [kubernetes] enable_tcp_keepalive for new installs to True (#15338)
• Fixed #14270: Add error message in OOM situations (#15207)
• Better compatibility/diagnostics for arbitrary UID in docker image (#15162)
• Updates 3.6 limits for latest versions of a few libraries (#15209)
• Adds Blinker dependency which is missing after recent changes (#15182)
• Remove 'conf' from search_columns in DagRun View (#15099)
• More proper default value for namespace in K8S cleanup-pods CLI (#15060)
• Faster default role syncing during webserver start (#15017)
• Speed up webserver start when there are many DAGs (#14993)
• Much easier to use and better documented Docker image (#14911)
• Use libyaml C library when available. (#14577)
• Don't create unittest.cfg when not running in unit test mode (#14420)
• Webserver: Allow Filtering TaskInstances by queued_dttm (#14708)
• Update Flask-AppBuilder dependency to allow 3.2 (and all 3.x series) (#14665)
• Remember expanded task groups in browser local storage (#14661)
• Add plain format output to cli tables (#14546)
• Make airflow dags show command display TaskGroups (#14269)
• Increase maximum size of extra connection field. (#12944)
• Speed up clear_task_instances by doing a single sql delete for TaskReschedule (#14048)
• Add more flexibility with FAB menu links (#13903)
• Add better description and guidance in case of sqlite version mismatch (#14209)

Doc only changes

• Add documentation create/update community providers (#15061)
• Fix mistake and typos in airflow.utils.timezone docstrings (#15180)
• Replace new url for Stable Airflow Docs (#15169)
• Docs: Clarify behavior of delete_worker_pods_on_failure (#14958)
• Create a documentation package for Docker image (#14846)
• Multiple minor doc (OpenAPI) fixes (#14917)
• Replace Graph View Screenshot to show Auto-refresh (#14571)

Misc/Internal

• Import Connection lazily in hooks to avoid cycles (#15361)
• Rename last_scheduler_run into last_parsed_time, and ensure it's updated in DB (#14581)
• Make TaskInstance.pool_slots not nullable with a default of 1 (#14406)
• Log migrations info in consistent way (#14158)