PrefectHQ/prefect 3.4.21

3.4.21 - Memory Lane Has a TTL

on GitHub

Released on October 02, 2025

Enhancements ➕➕

• Add automatic local dependency discovery for flow bundles by @desertaxle in #19043
• Allow serving instance methods by @desertaxle in #19070
• Add task run tags as related resources on task run events by @chrisguidry in #19059
• Enable configurable lease timeout durations by @solms in #19058
• Improve CLI import performance by @zzstoatzz in #19078

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: 3.4.20...3.4.21