1.27.0
💥 External Storage Reference Format Change (Experimental)
External storage reference event history format has been incompatibly changed from prerelease. New storage references are emitted in the new format starting with release. Support for the ability to retrieve references in the old format has been preserved. The prerelease format is deprecated and will be removed in a future release.
Workflow Streams
This release adds Workflow Streams, a public preview contrib library that gives a workflow a durable, offset-addressed event channel for keeping outside observers updated on workflow and activity progress. It's built on Temporal's existing signals, updates, and queries, with batching, exactly-once deduplication, topic filtering, and continue-as-new helpers layered on top. Intended uses are streaming UIs for long-running AI agents, status for in-flight payment or order processing, and progress for data pipelines. It is not for not ultra-low-latency cases like real-time voice.
What's Changed
- Harden flaky workflow tests by @tconley1428 in #1456
- Pin GitHub Actions and cap uv deps by @tconley1428 in #1458
- Implement
is_running()for asyncio loop by @brianstrauch in #1463 - chore: Update and pin all GHA actions by @mjameswh in #1464
- Fix flaky OpenAI test timeouts by @DABH in #1466
- AI-60: Add summary_fn parameter to TemporalModel for dynamic activity summaries by @xumaple in #1451
- Add OTel tracing for standalone activities by @cconstable in #1471
- More TMPRL1104 logging details by @jmaeagle99 in #1469
- Fix external storage CaN test stability by @jmaeagle99 in #1454
- Fix race condition in test_update_payload_conversion by @brianstrauch in #1473
- Fix race condition in test_async_response by @brianstrauch in #1474
- Fix race condition in test_cancellation_type for TRY_CANCEL by @brianstrauch in #1475
- Extend Workflow timeout for test_customer_service_workflow by @brianstrauch in #1476
- Update sdk-core submodule to latest by @jmaeagle99 in #1481
- Add AI Foundations as CODEOWNERs of AI plugins by @donald-pinckney in #1482
- chore: update submodule to sdk-rust by @chris-olszewski in #1480
- AI-36: Add LangGraph plugin by @brianstrauch in #1448
- 💥 Use ExternalStorageReference protobuf message for payload references by @jmaeagle99 in #1486
- External storage: Improved debuggability for region problems. by @drewhoskins-temporal in #1487
- Add start_delay for SAA by @Sushisource in #1491
- Update Python and Cargo lockfiles by @tconley1428 in #1483
- Add Workflow Streams library by @jssmith in #1423
Core Changes
2026-04-10 - 08adc4a4 - feat(sdk): add typed continue as new (temporalio/sdk-rust#1209)
2026-04-14 - 00d3888a - feat(client): ergonomic workflow description (temporalio/sdk-rust#1215)
2026-04-14 - c78bfb67 - Support static_summary, static_details and current_details` in the Rust sdk (temporalio/sdk-rust#1208)
2026-04-14 - d24a6f77 - chore(ci): bump macos-intel timeout (temporalio/sdk-rust#1214)
2026-04-15 - d7ebff81 - Add DNS load balancing (temporalio/sdk-rust#1212)
2026-04-16 - 33b86805 - fix(sdk): normalize how user metadata is encoded (temporalio/sdk-rust#1216)
2026-04-16 - 33c6c5e2 - Optimize dependencies (temporalio/sdk-rust#1219)
2026-04-16 - 72d8c5d3 - Fix test broken on windows by fake server binding to ipv6 (temporalio/sdk-rust#1220)
2026-04-16 - 904f4793 - Remove unused parking lot send guard feature (temporalio/sdk-rust#1218)
2026-04-17 - 1e67b234 - chore: Update and pin all GHA actions (temporalio/sdk-rust#1222)
2026-04-20 - 9171aca4 - 💥 feat(sdk): enforce some activity to close timeout is set (temporalio/sdk-rust#1221)
2026-04-21 - 703fe6b2 - Fix NDE when multiple patches in a single WFT exceed SA's 2048-byte limit (temporalio/sdk-rust#1225)
2026-04-22 - 984da134 - Set WFT Failed cause on grpc message too large incidents (temporalio/sdk-rust#1229)
2026-04-23 - 64cb6ed2 - Shutdown rpc initiate shutdown (temporalio/sdk-rust#1224)
2026-04-24 - 6dd29f2d - chore: rename master -> main in docs/crates/workflows (temporalio/sdk-rust#1233)
2026-04-25 - 30c4a313 - bump versions to 0.3.0 (temporalio/sdk-rust#1235)
2026-04-26 - 2872b536 - Update upstream api to latest (temporalio/sdk-rust#1234)
New Contributors
- @brianstrauch made their first contribution in #1463
- @DABH made their first contribution in #1466
- @cconstable made their first contribution in #1471
Full Changelog: 1.26.0...1.27.0
