New Features

• Add Data-aware Scheduling (https://github.com/apache/airflow/pulls?q=is%3Apr+is%3Amerged+label%3AAIP-48+milestone%3A%22Airflow+2.4.0%22)
• Add @task.short_circuit TaskFlow decorator (#25752)
• Make execution_date_or_run_id optional in tasks test command (#26114)
• Automatically register DAGs that are used in a context manager (#23592, #26398)
• Add option of sending DAG parser logs to stdout. (#25754)
• Support multiple DagProcessors parsing files from different locations. (#25935)
• Implement ExternalPythonOperator (#25780)
• Make execution_date optional for command dags test (#26111)
• Implement expand_kwargs() against a literal list (#25925)
• Add trigger rule tooltip (#26043)
• Add conf parameter to CLI for airflow dags test (#25900)
• Include scheduled slots in pools view (#26006)
• Add output property to MappedOperator (#25604)
• Add roles delete command to cli (#25854)
• Add Airflow specific warning classes (#25799)
• Add support for TaskGroup in ExternalTaskSensor (#24902)
• Add @task.kubernetes taskflow decorator (#25663)
• Add a way to import Airflow without side-effects (#25832)
• Let timetables control generated run_ids. (#25795)
• Allow per-timetable ordering override in grid view (#25633)
• Grid logs for mapped instances (#25610, #25621, #25611)
• Consolidate to one schedule param (#25410)
• DAG regex flag in backfill command (#23870)
• Adding support for owner links in the Dags view UI (#25280)
• Ability to clear a specific DAG Run's task instances via REST API (#23516)
• Possibility to document DAG with a separate markdown file (#25509)
• Add parsing context to DAG Parsing (#25161)
• Implement CronTriggerTimetable (#23662)
• Add option to mask sensitive data in UI configuration page (#25346)
• Create new databases from the ORM (#24156)
• Implement XComArg.zip(*xcom_args) (#25176)
• Introduce sla_miss metric (#23402)
• Implement map() semantic (#25085)
• Add override method to TaskGroupDecorator (#25160)
• Implement expand_kwargs() (#24989)
• Add parameter to turn off SQL query logging (#24570)
• Add DagWarning model, and a check for missing pools (#23317)
• Add Task Logs to Grid details panel (#24249)
• Added small health check server and endpoint in scheduler(#23905)
• Add built-in External Link for ExternalTaskMarker operator (#23964)
• Add default task retry delay config (#23861)
• Add clear DagRun endpoint. (#23451)
• Add support for timezone as string in cron interval timetable (#23279)
• Add auto-refresh to dags home page (#22900, #24770)

Improvements

• Add more weekday operator and sensor examples #26071 (#26098)
• Add subdir parameter to dags reserialize command (#26170)
• Update zombie message to be more descriptive (#26141)
• Only send an SlaCallbackRequest if the DAG is scheduled (#26089)
• Promote Operator.output more (#25617)
• Upgrade API files to typescript (#25098)
• Less hacky double-rendering prevention in mapped task (#25924)
• Improve Audit log (#25856)
• Remove mapped operator validation code (#25870)
• More DAG(schedule=...) improvements (#25648)
• Reduce operator_name dupe in serialized JSON (#25819)
• Make grid view group/mapped summary UI more consistent (#25723)
• Remove useless statement in task_group_to_grid (#25654)
• Add optional data interval to CronTriggerTimetable (#25503)
• Remove unused code in /grid endpoint (#25481)
• Add and document description fields (#25370)
• Improve Airflow logging for operator Jinja template processing (#25452)
• Update core example DAGs to use @task.branch decorator (#25242)
• Update DAG audit_log route (#25415)
• Change stdout and stderr access mode to append in commands (#25253)
• Remove getTasks from Grid view (#25359)
• Improve taskflow type hints with ParamSpec (#25173)
• Use tables in grid details panes (#25258)
• Explicitly list @dag arguments (#25044)
• More typing in SchedulerJob and TaskInstance (#24912)
• Patch getfqdn with more resilient version (#24981)
• Replace all NBSP characters by whitespaces (#24797)
• Re-serialize all DAGs on airflow db upgrade (#24518)
• Rework contract of try_adopt_task_instances method (#23188)
• Make expand() error vague so it's not misleading (#24018)
• Add enum validation for [webserver]analytics_tool (#24032)
• Add dttm searchable field in audit log (#23794)
• Allow more parameters to be piped through via execute_in_subprocess (#23286)
• Use func.count to count rows (#23657)
• Remove stale serialized dags (#22917)
• AIP45 Remove dag parsing in airflow run local (#21877)
• Add support for queued state in DagRun update endpoint. (#23481)
• Add fields to dagrun endpoint (#23440)
• Use sql_alchemy_conn for celery result backend when result_backend is not set (#24496)

Bug Fixes

• Have consistent types between the ORM and the migration files (#24044, #25869)
• Disallow any dag tags longer than 100 char (#25196)
• Add the dag_id to AirflowDagCycleException message (#26204)
• Properly build URL to retrieve logs independently from system (#26337)
• For worker log servers only bind to IPV6 when dual stack is available (#26222)
• Fix TaskInstance.task not defined before handle_failure (#26040)
• Undo secrets backend config caching (#26223)
• Fix faulty executor config serialization logic (#26191)
• Show DAGs and Datasets menu links based on role permission (#26183)
• Allow setting TaskGroup tooltip via function docstring (#26028)
• Fix RecursionError on graph view of a DAG with many tasks (#26175)
• Fix backfill occasional deadlocking (#26161)
• Fix DagRun.start_date not set during backfill with --reset-dagruns True (#26135)
• Use label instead of id for dynamic task labels in graph (#26108)
• Don't fail DagRun when leaf mapped_task is SKIPPED (#25995)
• Add group prefix to decorated mapped task (#26081)
• Fix UI flash when triggering with dup logical date (#26094)
• Fix Make items nullable for TaskInstance related endpoints to avoid API errors (#26076)
• Fix BranchDateTimeOperator to be timezone-awreness-insensitive (#25944)
• Fix legacy timetable schedule interval params (#25999)
• Fix response schema for list-mapped-task-instance (#25965)
• Properly check the existence of missing mapped TIs (#25788)
• Fix broken auto-refresh on grid view (#25950)
• Use per-timetable ordering in grid UI (#25880)
• Rewrite recursion when parsing DAG into iteration (#25898)
• Find cross-group tasks in iter_mapped_dependants (#25793)
• Fail task if mapping upstream fails (#25757)
• Support / in variable get endpoint (#25774)
• Use cfg default_wrap value for grid logs (#25731)
• Add origin request args when triggering a run (#25729)
• Operator name separate from class (#22834)
• Fix incorrect data interval alignment due to assumption on input time alignment (#22658)
• Return None if an XComArg fails to resolve (#25661)
• Correct json arg help in airflow variables set command (#25726)
• Added MySQL index hint to use ti_state on find_zombies query (#25725)
• Only excluded actually expanded fields from render (#25599)
• Grid, fix toast for axios errors (#25703)
• Fix UI redirect (#26409)
• Require dag_id arg for dags list-runs (#26357)
• Check for queued states for dags auto-refresh (#25695)
• Fix upgrade code for the dag_owner_attributes table (#25579)
• Add map index to task logs api (#25568)
• Ensure that zombie tasks for dags with errors get cleaned up (#25550)
• Make extra link work in UI (#25500)
• Sync up plugin API schema and definition (#25524)
• First/last names can be empty (#25476)
• Refactor DAG pages to be consistent (#25402)
• Check expand_kwargs() input type before unmapping (#25355)
• Filter XCOM by key when calculating map lengths (#24530)
• Fix ExternalTaskSensor not working with dynamic task (#25215)
• Added exception catching to send default email if template file raises any exception (#24943)
• Bring MappedOperator members in sync with BaseOperator (#24034)

Misc/Internal

• Add automatically generated ERD schema for the MetaData DB (#26217)
• Mark serialization functions as internal (#26193)
• Remove remaining deprecated classes and replace them with PEP562 (#26167)
• Move dag_edges and task_group_to_dict to corresponding util modules (#26212)
• Lazily import many modules to improve import speed (#24486, #26239)
• FIX Incorrect typing information (#26077)
• Add missing contrib classes to deprecated dictionaries (#26179)
• Re-configure/connect the ORM after forking to run a DAG processor (#26216)
• Remove cattrs from lineage processing. (#26134)
• Removed deprecated contrib files and replace them with PEP-562 getattr (#26153)
• Make BaseSerialization.serialize "public" to other classes. (#26142)
• Change the template to use human readable task_instance description (#25960)
• Bump moment-timezone from 0.5.34 to 0.5.35 in /airflow/www (#26080)
• Fix Flask deprecation warning (#25753)
• Add CamelCase to generated operations types (#25887)
• Fix migration issues and tighten the CI upgrade/downgrade test (#25869)
• Fix type annotations in SkipMixin (#25864)
• Workaround setuptools editable packages path issue (#25848)
• Bump undici from 5.8.0 to 5.9.1 in /airflow/www (#25801)
• Add custom_operator_name attr to _BranchPythonDecoratedOperator (#25783)
• Clarify filename_template deprecation message (#25749)
• Use ParamSpec to replace ... in Callable (#25658)
• Remove deprecated modules (#25543)
• Documentation on task mapping additions (#24489)
• Remove Smart Sensors (#25507)
• Fix elasticsearch test config to avoid warning on deprecated template (#25520)
• Bump terser from 4.8.0 to 4.8.1 in /airflow/ui (#25178)
• Generate typescript types from rest API docs (#25123)
• Upgrade utils files to typescript (#25089)
• Upgrade remaining context file to typescript. (#25096)
• Migrate files to ts (#25267)
• Upgrade grid Table component to ts. (#25074)
• Skip mapping against mapped ti if it returns None (#25047)
• Refactor js file structure (#25003)
• Move mapped kwargs introspection to separate type (#24971)
• Only assert stuff for mypy when type checking (#24937)
• Bump moment from 2.29.3 to 2.29.4 in /airflow/www (#24885)
• Remove "bad characters" from our codebase (#24841)
• Remove xcom_push flag from BashOperator (#24824)
• Move Flask hook registration to end of file (#24776)
• Upgrade more javascript files to typescript (#24715)
• Clean up task decorator type hints and docstrings (#24667)
• Preserve original order of providers' connection extra fields in UI (#24425)
• Rename charts.css to chart.css (#24531)
• Rename grid.css to chart.css (#24529)
• Misc: create new process group by set_new_process_group utility (#24371)
• Airflow UI fix Prototype Pollution (#24201)
• Bump moto version (#24222)
• Remove unused [github_enterprise] from ref docs (#24033)
• Clean up f-strings in logging calls (#23597)
• Add limit for JPype1 (#23847)
• Simply json responses (#25518)
• Add min attrs version (#26408)

Doc only changes

• Add url prefix setting for Celery Flower (#25986)
• Updating deprecated configuration in examples (#26037)
• Fix wrong link for taskflow tutorial (#26007)
• Reorganize tutorials into a section (#25890)
• Fix concept doc for dynamic task map (#26002)
• Update code examples from "classic" operators to taskflow (#25845, #25657)
• Add instructions on manually fixing MySQL Charset problems (#25938)
• Prefer the local Quick Start in docs (#25888)
• Fix broken link to Trigger Rules (#25840)
• Improve docker documentation (#25735)
• Correctly link to Dag parsing context in docs (#25722)
• Add note on task_instance_mutation_hook usage (#25607)
• Note that TaskFlow API automatically passes data between tasks (#25577)
• Update DAG run to clarify when a DAG actually runs (#25290)
• Update tutorial docs to include a definition of operators (#25012)
• Rewrite the Airflow documentation home page (#24795)
• Fix task-generated mapping example (#23424)
• Add note on subtle logical date change in 2.2.0 (#24413)
• Add missing import in best-practices code example (#25391)