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)