Dagster 1.13.14 - Serverless IO Manager Fixes

Dagster 1.13.14 was published on July 16, 2026, with two corrections for serverless asset materialization. The main operator impact is that organizations with more than one full deployment should no longer see the serverless I/O manager reject materialization with an HTTP 401 response.

The full release notes and downloads are on the GitHub release page.

The first fix applies to organizations that have more than one full deployment. Before this release, the serverless I/O manager could return a 401 error while materializing an asset in that layout. The affected condition is specific: the notes name multiple full deployments, not asset execution in general.

A 401 response normally sends an operator toward tokens, permissions, and identity configuration. That signal was not enough to explain this failure. The release notes do not identify the internal cause, so the fix should not be described as a token change or a permissions change. What is documented is the result: serverless I/O manager materialization no longer fails with 401 under the stated deployment topology.

For rollout verification, use an organization that actually has more than one full deployment. Run representative asset materializations in each relevant deployment context and confirm that the serverless I/O manager completes without the previous response. A test against only one full deployment does not exercise the condition named in the release.

The second fix covers asset storage keys that contain special characters. Those keys could cause the serverless I/O manager to return a 400 error during materialization. Dagster 1.13.14 corrects that request failure.

The notes do not list the affected characters, key formats, or encoding path. That omission matters when building a regression check. Do not guess one punctuation character and treat a passing result as complete coverage. Select representative keys from the existing asset catalog, especially keys that previously produced the 400 response, then materialize those assets through the same serverless I/O manager path.

This fix is about request acceptance at the I/O manager boundary. It does not announce a storage schema change, a new naming convention, or a migration for existing keys. Teams should therefore preserve real key values in their test fixtures instead of rewriting them to simpler names before testing the patch.

The release is named 1.13.14 for core and 0.29.14 for libraries. It is a stable release, not a prerelease. Its published notes contain exactly two bug fixes, with no listed feature additions, configuration changes, migration steps, or breaking changes.

The practical upgrade case is narrow. Teams using the serverless I/O manager should prioritize the patch if they operate multiple full deployments or have observed 400 responses for storage keys with special characters. Teams outside those conditions should not infer unrelated scheduler, execution, or storage improvements from this release.

After deployment, check materialization results and server responses for both documented cases. Keep the previous failing inputs available until the verification run completes. The Dagster 1.13.14 release page is the authoritative scope for this patch, and it does not provide a broader root cause analysis.