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3.4.25 - A slice of π-thon

Released on October 23, 2025 Enhancements ➕➕ Bug Fixes 🐞
  • Upgrade Docker image SQLite to 3.50.4 to address CVE-2025-6965 by @desertaxle in #19214
  • Fix GitLab credentials for self-hosted instances and deploy tokens by @zzstoatzz in #19227
  • Make MemoryLockManager serializable with cloudpickle by @desertaxle in #19246
  • Suppress noisy concurrency warnings for automatic tag-based checks by @desertaxle in #19254
  • Fix work pool env vars being overwritten by variable defaults by @desertaxle in #19258
Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.24…3.4.25

3.4.24 - The Un-Crashening

Released on October 16, 2025 Enhancements ➕➕ Experimental 🧪 Bug Fixes 🐞
  • Mitigate memory leak in in-memory messaging system by @desertaxle in #19136
  • Fix duplicate env vars from work pools in Kubernetes jobs by @zzstoatzz in #19171
  • Fix ProcessPoolTaskRunner when submitting with wait_for by @desertaxle in #19172
  • Fix deployment name truncation in from_storage and afrom_storage by @zzstoatzz in #19179
  • Avoid transitioning flow run to crashed when user code has already finished successfully by @desertaxle in #19181
  • Fix worker crash from double-release of concurrency limiter token by @desertaxle in #19188
  • Fix worker/runner crashes when flow runs are deleted by @desertaxle in #19189
  • Fix race conditions in concurrency lease renewal by @bunchesofdonald in #19187
  • Fix RunInput.with_initial_data to preserve type annotations by @zzstoatzz in #19176
Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.23…3.4.24

3.4.23 - Would you like some API in your CLI?

Released on October 09, 2025 Enhancements ➕➕ Bug Fixes 🐞
  • Add support for day_or parameter in cron schedule configurations by @zzstoatzz in #19121
  • Fix interference in async cancellation handling from timeout_async context manager by @desertaxle in #19101
  • Fix recursive local module discovery in bundle serialization by @desertaxle in #19124
Development & Tidiness 🧹 Documentation 📓
  • docs: link to available integrations release notes by @rcash in #19108
  • Add ATProto social analytics dashboard example using Prefect Assets by @zzstoatzz in #18984
  • Add documentation for Prefect MCP server by @desertaxle in #19115
Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.22…3.4.23

3.4.22 - If Only Our Releases Had Transaction Rollbacks

Released on October 03, 2025 Bug Fixes 🐞
  • Fix startup errors when installed with pydantic 2.10 and Python 3.9 and 3.10 by @desertaxle in #19095
  • Fix async task transaction rollback from sync task by @zzstoatzz in #19097
Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.21…3.4.22

3.4.21 - Memory Lane Has a TTL

Released on October 02, 2025 Enhancements ➕➕ Bug Fixes 🐞
  • Improve deployment validation error messages by @desertaxle in #19038
  • Fix KeyError when running deployment without parameter schema by @zzstoatzz in #19055
  • Fix PREFECT_CLIENT_CUSTOM_HEADERS JSON string parsing by @zzstoatzz in #19052
  • Use TTLCache for memory-based CausalOrdering to prevent memory leaks by @desertaxle in #19061
  • Fix block type dispatch breaking validation of Block Unions by @GalLadislav in #18995
  • Update Postgres listener to respect application_name setting by @zzstoatzz in #19081
Development & Tidiness 🧹
  • Clean up lineage experiment by @zzstoatzz in #19041
  • Remove duplicate graphviz, bump typer, update lockfile by @zzstoatzz in #19051
  • Remove flaky serve interrupt integration test by @zzstoatzz in #19053
  • Rename server.concurrency.initial_lease_timeout to server.concurrency.initial_deployment_lease_duration by @desertaxle in #19085
  • Normalize empty parameter_openapi_schema to valid OpenAPI format by @zzstoatzz in #19072
  • Keep DeploymentCreate.parameter_openapi_schema field Optional by @zzstoatzz in #19089
Documentation 📓
  • Improve automation actions documentation with type identifiers by @zzstoatzz in #19071
Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.20…3.4.21

3.4.20 - Search Party

Released on September 25, 2025 Enhancements ➕➕ Bug Fixes 🐞 Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.19…3.4.20

3.4.19 - Pay No Attention To That GCL Behind The Curtain

Released on September 19, 2025 Enhancements ➕➕ Bug Fixes 🐞 Development & Tidiness 🧹 Documentation 📓
  • fix: add redirect setting to docs.json to fix /latest path 404s by @zzstoatzz in #18945
  • fix: add errors.404.redirect setting to fix /latest path 404s by @zzstoatzz in #18946
Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.18…3.4.19

3.4.18 - He who holds the leases controls the universe

Released on September 12, 2025 Enhancements ➕➕ Bug Fixes 🐞 Development & Tidiness 🧹 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.17…3.4.18

3.4.17 - Distribution Matters

Released on September 05, 2025 Bug Fixes 🐞 Development & Tidiness 🧹 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.16…3.4.17

3.4.16 - Background Noise Reduction

Released on September 05, 2025 Enhancements ➕➕
  • Wait until determining deployment create or update to add deployment schedules by @kevingrismore in #18823
  • Display postgresql version on prefect version by @hanhwanglim in #18836
  • More robust write_path method in RemoteFileSystem to handle SMB UNC paths. by @tom21100227 in #18824
Bug Fixes 🐞 Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.15…3.4.16

3.4.15 - Emit me maybe

Released on August 29, 2025 New Features 🎉
  • Event emission from the command line with prefect event emit Emit events directly from external systems with the new prefect event emit CLI command. Perfect for triggering deployment runs from CI/CD!
    prefect event emit user.logged_in --resource-id user-123
    prefect event emit order.shipped --resource-id order-456 --payload '{"tracking": "ABC123"}'
    
    by @zzstoatzz in #18813
Enhancements ➕➕ Bug Fixes 🐞 Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.14…3.4.15

3.4.14 - Ctrl+C, Ctrl+V

Released on August 21, 2025 New Features 🎉
  • Environment Migration with prefect transfer Transfer your Prefect setup between backends with a single command! Idempotently migrate work pools, deployments, blocks, variables, and concurrency limits between self-hosted servers and Prefect Cloud. Check the Prefect dev log for more info!
  • Parallel task execution with ProcessPoolTaskRunner This new task runner executes tasks in separate subprocesses and while maintaining run context so you get full observability while running in parallel. A great choice if you need parallelism, but aren’t ready to start using dask or ray. Check the PR for more info!
Enhancements ➕➕ Bug Fixes 🐞
  • Fix apprise notifications failing silently with prefect_default notification type by @zzstoatzz in #18720
  • Fix error log when using a concurrency limit with a lease in strict mode by @desertaxle in #18725
  • Fix total run time calculation for tasks by @desertaxle in #18759
Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.13…3.4.14

3.4.13 - No, Your Database Cannot Have a Little Lock, Even As a Treat

Released on August 14, 2025 Bug Fixes 🐞 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.12…3.4.13

3.4.12 - 20k magic in the air

Released on August 08, 2025 Bug Fixes 🐞 Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.11…3.4.12

3.4.11 - Heads up, the repo man is coming for your deployment concurrency slot

Released on July 31, 2025 Enhancements ➕➕ Bug Fixes 🐞
  • Allow automations to notify when the triggers service is disabled by @fatih-acar in #18577
  • Truncate oversized log messages to prevent ValueError and improve flow debuggability by @nrnavaneet in #18550
  • Fix async locking error by generating a unique holder for each transaction by @desertaxle in #18607
Integrations & Dependencies 🤝 prefect-azure
  • Add PREFECT_API_AUTH_STRING to secure environment variables for ACI worker by @desertaxle in #18624
prefect-aws
  • Add support for providing PREFECT_API_AUTH_STRING as a secret to ECS tasks by @desertaxle in #18620
prefect-dbt prefect-gcp
  • Add GCP secret support to CloudRunV2Worker for Prefect API key/auth string by @desertaxle in #18594
  • Add GCP secret support to CloudRunWorker for Prefect API credentials by @desertaxle in #18608
  • Improve performance of uploads to GCP bucket by @zzstoatzz in #18571
prefect-kubernetes
  • Allow specifying the key for an existing Kubernetes worker API auth string secret by @mitchnielsen in #18578
Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.10…3.4.11

3.4.10 - Lease and thank you

Released on July 22, 2025 Enhancements ➕➕
  • Update async concurrency context manager to use leases by @desertaxle in #18522
  • Update sync concurrency context manager to use leases by @desertaxle in #18535
  • Track concurrency limit lease creation time and use it to calculate occupancy seconds by @desertaxle in #18551
Integrations & Dependencies 🤝 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.9…3.4.10

3.4.9 - It’s the Lease We Can Do

Released on July 17, 2025 Enhancements ➕➕ Bug Fixes 🐞 Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.8…3.4.9

3.4.8 - Objects in Mirror Are JSONer Than They Appear

Released on July 10, 2025 Enhancements ➕➕
  • Add section on dynamic asset materialization by @cicdw in #18383
  • Add —output and -o flags to all inspect commands, supporting ‘json’ by @cicdw in #18390
  • add prefect automation create command by @zzstoatzz in #18452
  • Add setting for configuring custom headers by @cicdw in #18444
Bug Fixes 🐞
  • Fix UI URL generation for FlowRunResponse in Slack automations by @zzstoatzz in #18407
  • Fix broken Google-indexed documentation URLs with redirects by @zzstoatzz in #18409
  • Fix worker crash when flow file is missing during hook execution by @zzstoatzz in #18424
  • clear pull_steps when no storage on deployment by @zzstoatzz in #18446
  • Account for null pull steps in CLI by @cicdw in #18454
  • Use UUID path converter in all places by @cicdw in #18455
  • Fix visit_collection to properly handle shared references by @zzstoatzz in #18434
Integrations & Dependencies 🤝 Development & Tidiness 🧹 Documentation 📓 Uncategorized Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.7…3.4.8

3.4.7 - Stream a Little Stream of Logs

Released on June 26, 2025 Enhancements ➕➕ Bug Fixes 🐞 Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.6…3.4.7

3.4.6 - Per My Last NOTIFY

Released on June 11, 2025 📰 Check out Prefect Assets! Bug Fixes 🐞
  • use pg notify/listen for multi-server automation synchronization by @zzstoatzz in #18266
  • Remove versions of pydantic that produce thread safety issues by @cicdw in #18250
  • fix config validation for nested and constrained settings by @zzstoatzz in #18260
  • add note about long migrations with big tables by @zzstoatzz in #18268
  • Add automations prefix to validate route by @cicdw in #18277
  • Fix nested materialization behavior by @jakekaplan in #18265
Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.5…3.4.6

3.4.5 - Assets Have Been Materialized Internally

Released on June 07, 2025 To learn more, register for next week’s webinar here! New Features 💅 Bug Fixes 🐞 Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.4…3.4.5

3.4.4 - No Cache in the Banana Stand

Released on May 29, 2025 Enhancements ✨ Bug Fixes 🐞 Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.3…3.4.4

3.4.3 - You Return NotImplemented, I Return False. We Are Not The Same

Released on May 22, 2025 Enhancements ➕➕
  • add settings to configure asyncpg mtls by @29x10 in #18097
Bug Fixes 🐞
  • fix AttributeError during equality check after args/kwargs deletion by @zzstoatzz in #18110
  • handle list value envvar overrides for logging by @levzem in #18062
Development & Tidiness 🧹 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.2…3.4.3

3.4.2 - Stay classy

Released on May 19, 2025 Enhancements ➕➕
  • Support serving [@classmethod](https://github.com/classmethod) and [@staticmethod](https://github.com/staticmethod) flows by @vyagubov in #18065
Bug Fixes 🐞 Integrations & Dependencies 🤝 prefect-kubernetes prefect-docker prefect-shell Development & Tidiness 🧹 Documentation 📓
  • Adds Google site verification tag to our docs by @cicdw in #18031
Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.1…3.4.2

3.4.1 - Zen and the Art of Kubernetes Job Submission

Released on May 08, 2025 This release also ships with version 0.6.0 of prefect-kubernetes, featuring a revamped Kubernetes worker. The updated worker is more stateless, providing improved resiliency, enhanced event emission, and better crash detection capabilities. See #18004 for more details. Enhancements ➕➕ Bug Fixes 🐞 Integrations & Dependencies 🤝 Development & Tidiness 🧹
  • Add test covering .with_options when used with a classmethod flow by @vilhenad in #17647
  • Consolidate validation on self-validating types by @zzstoatzz in #17994
Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.4.0…3.4.1

3.4.0 - Pour one out for the flow run notification service

Released on May 02, 2025 This release removes the deprecated flow run notifications feature. Existing notification policies will be automatically migrated to automations when the server starts after upgrading. Notifications will continue to work as expected—no user action is required. Enhancements ➕➕ Bug Fixes 🐞
  • handle heartbeat event in wait_for_flow_run by @zzstoatzz in #17930
  • add parameters validator to DeploymentCreateFlowRun by @zzstoatzz in #17938
  • Fix links to Specify flow parameters section by @bkkkk in #17942
  • fix dead-lock between ConcurrentTaskRunner, wait_for, and tag concurrency limits by @zzstoatzz in #17943
  • Remove future garbage collection warning by @cicdw in #17954
  • fix: Specify project during Cloud Run provision by @danfairs in #17965
  • Remove extra="forbid" config on WorkPoolStorageConfiguration by @desertaxle in #17960
Development & Tidiness 🧹 Documentation 📓 Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.3.7…3.4.0