3.7 - Prefect

3.7.1 - Don’t touch that dial!

Released on May 16, 2026 Enhancements ➕➕

Add deployment_name logging variable by @devin-ai-integration[bot] in #21804
Infer logs page size from API response in CLI by @alighazi288 in #21711
Add default result storage CLI by @zzstoatzz in #21771
Add Pydantic-aware tojson template filter by @devin-ai-integration[bot] in #21861
Add worker channel protocol contract by @desertaxle in #21859
Add worker channel client with REST fallback by @desertaxle in #21885
Add worker cleanup executor by @desertaxle in #21895
Add worker work-pool snapshot handling by @desertaxle in #21898
Add cancelling_timeout_teardown.v1 cleanup handler by @desertaxle in #21911

Bug Fixes 🐞

Fix flow run logs download from Prefect UI in browser by @baltic-tea in #21718
Fix flow run suspension at orchestration boundaries by @desertaxle in #21875
Clear default result storage when deleting block by @zzstoatzz in #21862
Preserve trailing slash when redirecting to V2 UI by @zzstoatzz in #21912
Fix concurrency lease renewal starvation with thread-backed renewal by @desertaxle in #21925
Enforce tz-aware DateTime on Python >= 3.13 by @zzstoatzz in #21952
Fix subflow duplication when process is re-executed against same flow_run_id by @devin-ai-integration[bot] in #21951
Reject COMPLETED→COMPLETED transitions that discard result data by @saschwartz in #21956
Use tz-aware now("UTC") for last_adhoc_pull timestamp in runner by @J3r3myPerera in #21961
Guard .get() calls on arbitrary State.data in result-data-loss rules by @devin-ai-integration[bot] in #21967

Integrations & Dependencies 🤝

Development & Tidiness 🧹

Fix flaky test_flow_run_execute_cancellation_runs_nested_subflow_hooks by @devin-ai-integration[bot] in #21866
Migrate low-risk private modules to _internal (batch 1 of 3) by @devin-ai-integration[bot] in #21879
Migrate medium-complexity private modules to _internal (batch 2) by @devin-ai-integration[bot] in #21881
Migrate _result_records.py and utilities/_engine.py to _internal/ (batch 3) by @devin-ai-integration[bot] in #21880
Label agents-md-update PRs and exclude from changelog by @devin-ai-integration[bot] in #21910
Fix duplicated “the” in flow_run_slas test comments by @lphuc2250gma in #21943
Widen timing tolerance in test_renew_concurrency_lease by @devin-ai-integration[bot] in #21965
Fix flaky test_reschedule_flow_runs timeout under CI load by @devin-ai-integration[bot] in #21966
Harden AGENTS.md auto-sync reviews by @devin-ai-integration[bot] in #21975

Documentation 📓

Document default result storage by @zzstoatzz in #21774
Document published REST OpenAPI schema by @zzstoatzz in #21844
Mark server-side default result storage as beta by @zzstoatzz in #21877
Document context propagation for threads in add-logging guide by @jbbqqf in #21883
Recommend managed automation for zombie detection by @bunchesofdonald in #21894
Add unlisted infrastructure debugging overview page by @devin-ai-integration[bot] in #21900
Note metric-trigger Cloud gating and event prefix difference by @zzstoatzz in #21935

Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.7.0…3.7.1

Released on May 06, 2026 New Features 🎉

Enhancements ➕➕

Support inline block placeholder substitution by @hemantmm in #21777
Render Mermaid.js diagrams in Markdown blocks in ui-v2 by @devin-ai-integration[bot] in #21793
Eliminate O(N²) checksum scan in read_block_schemas by @VittoriaLanzo in #21754
Add per-browser UI version switcher by @desertaxle in #21706
Add server default result storage config surface by @zzstoatzz in #21532
Route server default result storage through runtime resolution by @zzstoatzz in #21759
Add flow.generate_mermaid_graph() method for dependency-free flow visualization by @znicholasbrown in #21786
Route flow-run execute through workspace resolver by @desertaxle in #21796
Add flow engine module entrypoint by @desertaxle in #21799
Run prepared pyproject workspaces with uv by @desertaxle in #21801
Warn when nested ThreadPoolTaskRunner submission would deadlock by @devin-ai-integration[bot] in #21800
Add cycle detection for block_document references by @Lougarou in #21829

Bug Fixes 🐞

Use now() helper instead of DateTime.now() in deployment CLI by @devin-ai-integration[bot] in #21769
Fix race condition in GitRepository.pull_code() with file-based locking by @devin-ai-integration[bot] in #21388
Retry record_bulk_task_run_events on IntegrityError by @devin-ai-integration[bot] in #21813
Set custom flow run names before Running events by @devin-ai-integration[bot] in #21803
Prevent deadlock in mark_deployments_ready / mark_deployments_not_ready by @chuqCTC in #21792
Fix V2 concurrency lease release errors by @devin-ai-integration[bot] in #21797

Development & Tidiness 🧹

Avoid run_coro_as_sync deadlock in wait futures test by @devin-ai-integration[bot] in #21766
Widen timing tolerance for test_flow_run_lateness_when_scheduled by @devin-ai-integration[bot] in #21781
Widen flow timeout in test_timeout_concurrency_slot_released by @devin-ai-integration[bot] in #21788
Add apt retry config to old-sqlite.Dockerfile by @devin-ai-integration[bot] in #21814
Use thread-based pytest-timeout for test_timeout_stops_execution_at_next_task_for_sync_flows by @devin-ai-integration[bot] in #21819
Add zombie flow detection trigger regression test by @devin-ai-integration[bot] in #21802

Full Changelog: https://github.com/PrefectHQ/prefect/compare/3.6.29…3.7.0