New Release: Ultralytics v8.4.39

[glenn-jocher]

Ultralytics v8.4.39 is out

Quick summary: Ultralytics v8.4.39 is a quality-and-usability release focused on cleaner run naming, better CLI coverage for Solutions, safer rotated-box training behavior, and clearer docs around the Ultralytics Platform and integrations. If you’re building with Ultralytics YOLO, this update should make day-to-day workflows smoother and more reliable.

Highlights

Cleaner default run naming

The biggest change in this release is that incremented run paths now use dashed naming like exp-2 and results-2.txt instead of exp2 and results2.txt.

This update landed in PR #24193 by @glenn-jocher and includes regression tests for both directory and file increment behavior. This should make experiment tracking easier to read when managing lots of runs.

New CLI parity for Solutions

You can now launch more Solutions workflows directly from the CLI:

• yolo solutions region
• yolo solutions security
• yolo solutions parking

This was added in PR #24251 by @raimbekovm, with docs updated to include CLI usage examples.

A couple of notes:

• Security email alerts still require Python API authentication
• Parking workflows require a prebuilt JSON file of parking zones

Safer rotated OBB training

A subtle but important fix in PR #24260 by @lmycross prevents unintended in-place modification of gt_bboxes inside RotatedTaskAlignedAssigner by cloning before edits.

This improves safety and stability for advanced rotated-box training pipelines.

Improvements

Reliability hardening for security alarms

The security alarm flow now checks whether a mail server is configured before attempting to send email, helping avoid unnecessary failures.

More resilient CI workflows

Automation reliability was improved in PR #24261 by @glenn-jocher:

• Added retry wrappers around Docker and registry logins
• Updated link-check retries to use fixed backoff within timeout budgets

These changes should reduce flaky CI and publishing failures.

Documentation and Platform updates

Several docs and platform clarity updates are included in this release:

• Redirected and outdated URLs were cleaned up in PR #24255 by @glenn-jocher
• Sony IMX500 docs now clarify supported variants in PR #24248 by @raimbekovm
• Neptune and MLflow docs were corrected in PR #24259 by @raimbekovm
• Docs now point users more clearly toward the Ultralytics Platform docs in PR #24262 by @raimbekovm
• The AP data region label was corrected to Taiwan in PR #24264 by @raimbekovm
• Pro plan RBAC availability was clarified in PR #24263 by @raimbekovm

Why this release matters

• Cleaner experiment management with exp-2 style naming
• Faster CLI adoption for region, security, and parking Solutions
• Safer OBB training with fewer hidden side effects
• More reliable automation in CI workflows
• Clearer onboarding and docs for Platform and integrations

Try it out

If you want to upgrade right away, you can install the latest release with:

pip install -U ultralytics

You can also explore the latest models on the Ultralytics YOLO26 page. YOLO26 remains the recommended choice for new projects, while YOLO11 is still fully supported.

Full changelog

You can review the complete diff in the v8.4.38 to v8.4.39 changelog, or browse the release directly on the v8.4.39 release page.

Thanks to everyone who contributed improvements to this release Please give v8.4.39 a try and share feedback, issues, or ideas with us in the community.