3.9 - Prefect

3.9.1 - This hour is a rerun

Released on October 30, 2026 Enhancements ➕➕

Add custom state discovery and filters by @desertaxle in #23490
Add Run action to the React flows list menu and flow page by @devin-ai-integration[bot] in #23354
Allow sorting task runs by duration by @nolantonio in #23275
Allow dismissing the V1 UI sidebar shortcut by @zzstoatzz in #23626
Enforce duration input minimum by @uinstinct in #23122
Cache get_timezones() by @tylerjthomas9 in #23531
Share orchestration clients across automation actions by @fatih-acar in #23255
Restore advisory Cloud API compatibility checks by @desertaxle in #23624
Show plain IDs instead of UUID(...) reprs in CLI messages by @LuisFigueroaG in #23650
Align date picker popover to the start instead of center by @uinstinct in #23655

Bug Fixes 🐞

Prevent state persistence error from failing success flow by @uinstinct in #22745
Skip unset Pydantic private attributes when rebuilding models in visit_collection by @devin-ai-integration[bot] in #23515
Retry flows that return a failed state when retries is configured by @devin-ai-integration[bot] in #23535
Preserve literal markup and emoji aliases in variable CLI JSON output by @devin-ai-integration[bot] in #23530
Resolve numeric string dict keys in get_from_dict by @devin-ai-integration[bot] in #23454
Begin SQLite write transaction before reading automation buckets by @devin-ai-integration[bot] in #23471
Fix forked child processes exiting with code 1 because of QueueService at-exit drain by @devin-ai-integration[bot] in #23464
Serialize context on every ProcessPoolTaskRunner.submit() by @devin-ai-integration[bot] in #23376
Schedule astop on SIGTERM instead of dropping the coroutine by @devin-ai-integration[bot] in #23346
Keep flows search input focused while filtering by @devin-ai-integration[bot] in #23338
Keep daily IntervalSchedule wall-clock time across DST when start is after the change by @devin-ai-integration[bot] in #23205
Allow the provisioned ECS execution role to create CloudWatch log groups by @Sagargupta16 in #23557
Fix GitRepository.pull_code() re-cloning a shallow clone on every new commit by @CassianoE in #23351
Substitute apply_values placeholders in a single pass by @devin-ai-integration[bot] in #23494
Percent-encode path values in url_for by @devin-ai-integration[bot] in #23493
Read automation buckets in a single query to avoid refresh race by @devin-ai-integration[bot] in #23604
Delete every automation with prefect automation delete --all by @cf3901646 in #23521
Apply both any_ and not_any_ in flow run state filters by @spicysharkco in #23459
Fix JSON flow results with data or result keys reading back wrong by @devin-ai-integration[bot] in #23377
Preserve deployment concurrency lease ID on forced flow run state changes by @darshjoshi in #23304
Fix filter_files aborting on a directory symlink cycle by @aayushbaluni in #23307
Preserve cron start bounds in repeated DST hours by @zzstoatzz in #23634
Recover cron occurrences shifted through DST gaps by @zzstoatzz in #23636
Exit non-zero from flow-run execute when a crash cannot be reported by @devin-ai-integration[bot] in #23393
Skip repeated cron occurrences during scheduler refills by @zzstoatzz in #23652
Stop extra cron runs during DST refills on Python 3.11 and 3.12 by @desertaxle in #23672
Fall back to placeholder for any jsonable_encoder error in Flow.serialize_parameters by @devin-ai-integration[bot] in #23630
Fix 500 from flow run list endpoints when a parameter exceeds 64 bits by @DEVJHAWAR11 in #23429
Reset pause keys when a blocking pause is rescheduled by @devin-ai-integration[bot] in #23399
Read until final state after terminal event in wait_for_flow_run by @devin-ai-integration[bot] in #23669
Display zero and false enum selections in the UI by @ashutosh8021 in #23656
Publish duration lower bounds only where validation enforces them by @gaker in #23507
Read metric triggers on metrics this version doesn’t know by @nathandpeterson in #23513
Fix duplicate retries label in deployments custom run by @uinstinct in #23343
Show a not-found error from prefect flow-run inspect for missing runs by @LuisFigueroaG in #23329
Show a not-found error from prefect deployment run --id for missing deployments by @LuisFigueroaG in #23586
Show an invalid ID error from prefect deployment run --id for malformed IDs by @LuisFigueroaG in #23621
Show an invalid slug error from prefect block inspect and block delete for extra slashes by @LuisFigueroaG in #23670
Read every global concurrency limit in prefect transfer by @spicysharkco in #23456
Add url property to client-side ReceivedEvent by @ethanstoner in #23181
Prevent incorrect cached task results by preserving DataFrame column order by @uinstinct in #23303
Raise ObjectUnsupported from the async create_work_pool when the plan doesn’t allow the pool by @LuisFigueroaG in #23610
Fix task returning another task’s cached results by @uinstinct in #23468
Make date range span relative instead of absolute by @uinstinct in #23086
Fix returned failed states being cached as successful task results by @uinstinct in #23523
Fix date changing when clicking pm in date selector by @uinstinct in #23622
Fix “use default value” doing nothing in parameter inputs by @uinstinct in #23657

Integrations & Dependencies 🤝

Make the server compatible with SQLAlchemy 2.1 by @devin-ai-integration[bot] in #23201
Lock current prefect-redis and prefect-kubernetes for the Docker image by @devin-ai-integration[bot] in #23537
Bump stale integration pins in uv.lock and keep them current on release by @devin-ai-integration[bot] in #23527
Upgrade cyclopts to 5.3.2 and keep CLI exit codes and command names by @gaker in #23646
Refresh the Python and UI dependency lockfiles by @gaker in #23666
Move the remaining Node 20 pins to Node 22 by @znicholasbrown in #23509
Update Node to the October 2026 security releases by @znicholasbrown in #23508
Bump vite from 8.2.2 to 8.3.4 in /ui-v2 by @dependabot[bot] in #23488
Bump opentelemetry-api from 1.44.0 to 1.45.1 by @dependabot[bot] in #23539
Bump zod from 4.5.4 to 4.6.7 in /ui-v2 by @dependabot[bot] in #23547
Bump graphql-core from 3.2.7 to 3.2.12 by @dependabot[bot] in #23542
Bump pillow from 12.3.0 to 13.0.0 by @dependabot[bot] in #23541
Bump virtualenv from 21.7.13 to 21.14.9 by @dependabot[bot] in #23540
Bump virtualenv from 21.14.9 to 21.14.13 by @dependabot[bot] in #23584
Bump storybook from 10.6.0 to 10.6.3 in /ui-v2 by @dependabot[bot] in #23549
Bump lodash-es and mermaid in /ui-v2 by @dependabot[bot] in #23551
Bump dompurify from 3.4.16 to 3.4.17 in /ui-v2 by @dependabot[bot] in #23548
Bump undici from 8.11.2 to 8.12.3 in /ui-v2 by @dependabot[bot] in #23581
Bump fast-uri from 3.1.7 to 3.1.9 in /ui-v2 by @dependabot[bot] in #23582
Bump msgpack from 1.2.1 to 1.2.3 by @dependabot[bot] in #23633
Bump qs from 6.16.0 to 6.17.0 in /ui by @dependabot[bot] in #23632

Development & Tidiness 🧹

Fix flaky TestRemoteFileSystem tree-project tests by @devin-ai-integration[bot] in #23554
Fix flaky worker channel tests racing a 1s wall-clock deadline by @devin-ai-integration[bot] in #23450
Fix flaky TestWorkerLogging test caused by logging leak from prefect config CLI tests by @devin-ai-integration[bot] in #23297
Fix flaky StateFilter discovery cap search test by @devin-ai-integration[bot] in #23556
Fix flaky date_diff_seconds from-now tests by @devin-ai-integration[bot] in #23451
Fix background worker shutdown hang when worker cancellation is lost by @devin-ai-integration[bot] in #23511
Ignore Python 3.15 multi-threaded fork warning in forked child service test by @devin-ai-integration[bot] in #23562
Fix flaky events E2E tests by filtering by exact resource IDs by @devin-ai-integration[bot] in #23579
Fix flaky TestProcessPoolTaskRunner::test_submit_remains_non_blocking by @devin-ai-integration[bot] in #23605
Fix flaky TestFlowRunLogs tests by filtering logs by flow run by @devin-ai-integration[bot] in #23611
Refresh and verify Docker image CA trust stores by @zzstoatzz in #23517
Document SQLite BEGIN IMMEDIATE contract in server AGENTS.md by @devin-ai-integration[bot] in #23560
Document _pendulum_call contract in src/prefect AGENTS.md by @devin-ai-integration[bot] in #23499

Documentation 📓

Document Python 3.15 support and ISO duration inputs for within by @devin-ai-integration[bot] in #23498
Document flow retries for returned Failed states by @devin-ai-integration[bot] in #23543
Document microbatch task runs and partial success in PrefectDbtRunner by @devin-ai-integration[bot] in #23361
Correct the reverse-proxy UI settings table by @himanshuchawla0807-gif in #23479
Document event.url in automation templates by @devin-ai-integration[bot] in #23607
Set canonical URLs to www.prefect.io by @maximearmstrong in #23641
Link to the docs at www.prefect.io/docs by @maximearmstrong in #23642
Fix broken docs links and stop redirecting missing pages to the homepage by @maximearmstrong in #23651

Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.9.0…3.9.1

3.9.0 - Pendulum’s last swing

Released on October 21, 2026 Breaking Changes ⚠️

Drop Python 3.10 support by @devin-ai-integration[bot] in #23324
Remove deprecated Runner execution paths by @desertaxle in #23496
Deprecate Pendulum datetime behavior on Python 3.11–3.12 by @devin-ai-integration[bot] in #23328

New Features 🎉

Add Python 3.15 support by @devin-ai-integration[bot] in #23400

Enhancements ➕➕

Add opt-in clearing for empty deployment schedules by @mifuha in #23412
Cut CPU spent delivering events and API logs by @desertaxle in #23473
Open a run’s artifacts directly from the Artifacts tab and run graph in ui-v2 by @JonasFockstedt in #23339
Read automations with action types this version doesn’t know by @nathandpeterson in #23426
Recover cancellation and suspension observers from websocket outages by @devin-ai-integration[bot] in #23421

Bug Fixes 🐞

Keep the runner healthcheck healthy while the API is in maintenance by @jimid27 in #23325
Skip duplicate worker submissions of runs that already hold a limit slot by @devin-ai-integration[bot] in #23341
Fix prefect.yaml creation when optional contents is omitted by @MuhammadWaleed12 in #23334
Check out pinned commit_sha when a git checkout already exists by @devin-ai-integration[bot] in #23374
Preserve pytz timezone names in RRuleSchedule.from_rrule() by @devin-ai-integration[bot] in #23396
Fix visit_collection returning another object’s cached result after id reuse by @novain-shibu in #23404
Make *args/**kwargs optional collections in flow parameter schemas by @devin-ai-integration[bot] in #23418
Return run input from async pause_flow_run when pause is rejected by @devin-ai-integration[bot] in #23435
Allow Task.with_options(tags=[]) to clear existing tags by @devin-ai-integration[bot] in #23444
Delete every deployment with prefect deployment delete --all by @devin-ai-integration[bot] in #23440
Unwrap FieldInfo defaults for unmapped parameters in task.map() by @devin-ai-integration[bot] in #23369
Count expect events that race or precede a proactive trigger’s window by @chrisguidry in #23445
Respect --hours in work-pool preview and work-queue preview --pool by @LuisFigueroaG in #23300
Raise ValueError for negative timeout in pause_flow_run by @kingsley-123 in #22761
Fix prefect deploy dropping list items templated from step outputs by @MohammadHijjawi97 in #23381
Copy hook lists in with_options for tasks and flows by @spicysharkco in #23442
Return empty list from extract_instances when there is no match by @udsy19 in #23427
Fix timeout=0 raising a TimeoutError in PrefectFutureList.result by @uinstinct in #23408
Fix silently skipped task retries in retry_condition_fn by @uinstinct in #23397
Fix overlapping action branches in the automation JSON schema by @devin-ai-integration[bot] in #23448
Use min_length and max_length on request bodies so the server imports on FastAPI 0.155 by @bunchesofdonald in #23476
Make flow run activity cells navigable by @VivekVRobo in #23352
Render run graph artifact icons instead of black boxes in ui-v2 by @JonasFockstedt in #23348

Integrations & Dependencies 🤝

Bump source-map-js from 1.2.1 to 1.2.2 in /ui by @dependabot[bot] in #23315
Bump postcss-selector-parser from 6.1.2 to 6.1.4 in /ui by @dependabot[bot] in #23288
Bump seroval from 1.6.2 to 1.6.8 in /ui-v2 by @dependabot[bot] in #23314
Bump snowflake-connector-python from 4.7.1 to 4.7.3 by @dependabot[bot] in #23316
Bump werkzeug from 3.1.6 to 3.1.9 by @dependabot[bot] in #23317
Bump mako from 1.3.12 to 1.4.2 by @dependabot[bot] in #23318
Bump multidict from 6.7.0 to 6.9.1 by @dependabot[bot] in #23319
Bump uv from 0.12.10 to 0.12.18 in /scripts/proxy-test by @dependabot[bot] in #23365
Bump cairosvg from 2.9.0 to 2.9.1 by @dependabot[bot] in #23363
Bump source-map-js from 1.2.1 to 1.2.2 in /ui-v2 by @dependabot[bot] in #23364
Bump dompurify from 3.4.12 to 3.4.16 in /ui-v2 by @dependabot[bot] in #23362
Bump aiohttp from 3.14.3 to 3.14.4 by @dependabot[bot] in #23462
Bump follow-redirects from 1.16.0 to 1.16.1 in /ui by @dependabot[bot] in #23480
Bump vite from 8.2.2 to 8.3.4 in /ui by @dependabot[bot] in #23485
Cap fastapi below 0.151 by @bunchesofdonald in #23478
Update certifi and uv for the eMudhra CA compromise by @desertaxle in #23483

Development & Tidiness 🧹

Keep the patched test clock timezone-aware on Python 3.12 by @chrisguidry in #23465
Wait for the events client to confirm events before asserting in checkpoint tests by @bunchesofdonald in #23477
Guard internal call sites against Pendulum deprecation warnings by @devin-ai-integration[bot] in #23497
Replace dead Sanity logo URLs in bundled collection metadata by @mattiamatrix in #23409

Documentation 📓

Fix broken in-page anchors in the events reference by @wznhf78gyf-bot in #23331
Fix items type in the base job template customization docs by @rjafarau in #23388
Document UnknownAction for automations and transfer skips by @devin-ai-integration[bot] in #23446
Document held expect events for proactive triggers with after by @devin-ai-integration[bot] in #23467

Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.8.8…3.9.0

​3.9.1 - This hour is a rerun

​3.9.0 - Pendulum’s last swing

3.9.1 - This hour is a rerun

3.9.0 - Pendulum’s last swing