●Change8

Migrating to MLflow v3.6.0rc0

Version v3.6.0rc0 introduces 1 breaking change. This guide details how to update your code.

Released: 11/4/2025

1
Breaking Changes
4
Migration Steps
6
Affected Symbols

⚠️ Check Your Code

If you use any of these symbols, you need to read this guide:

mlflow.tracking.backend.FilesystemStoremlflow.tracking.backend.SQLiteStoremlflow.tracing.span._deduplicate_span_namemlflow.server.AgentServermlflow.ui.trace.TraceUImlflow.tracing.sdk.VercelAITracer

Breaking Changes

●Issue #1

[Tracing] Span name deduplication has been removed, which may affect code that relied on automatic deduplication of span names. Update custom tracing logic to handle unique span names manually.

Migration Steps

  1. 1
    Switch tracking store configuration from `filesystem` to `sqlite` in `mlflow.set_tracking_uri` or `mlflow.tracking` settings.
  2. 2
    Run `mlflow db upgrade` to migrate existing tracking data to SQLite if needed.
  3. 3
    Review any custom tracing code that relied on automatic span name deduplication and ensure unique span names are provided.
  4. 4
    Test your pipelines against the new Agent Server if you were using the previous agent deployment mechanism.

Release Summary

MLflow 3.6.0rc0 adds full OpenTelemetry support, session‑level trace UI, a new experiment tab layout, Vercel AI TypeScript tracing, cost tracking for LLM judges, and an Agent Server, while deprecating the filesystem backend and removing span name deduplication.

Need More Details?

View the full release notes and all changes for MLflow v3.6.0rc0.

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