ultralytics 8.4.23

v8.4.23 - `ultralytics 8.4.23` Refactor `AutoBackend` into modular per-backend classes (#23790)

on Python PyPI

🌟 Summary

Ultralytics v8.4.23 is mainly a big under-the-hood inference upgrade 🚀: AutoBackend was fully redesigned into modular backend classes, making multi-format model deployment cleaner, easier to maintain, and more reliable across platforms.

📊 Key Changes

• Major architecture refactor (PR #23790 by @Laughing-q) 🧩

  • AutoBackend moved from one large file to a modular backend system (ultralytics/nn/backends/).
  • Added dedicated backend classes for many runtimes: PyTorch, TorchScript, ONNX/IMX, OpenVINO, TensorRT, TensorFlow/TFLite, Paddle, NCNN, MNN, RKNN, Triton, ExecuTorch, Axelera, and CoreML.
  • Introduced a shared BaseBackend interface to standardize model loading, metadata handling, and forward inference behavior.
  • AutoBackend now uses a single format route + backend map instead of many backend boolean flags.
  • Inference call sites (predict/validate/solutions) were updated to align with the new format-driven backend behavior (channels, format, warmup paths, etc.).
  • Added extensive backend reference docs pages under docs/en/reference/nn/backends/.

• Pose dataset conversion improvement (PR #23921 by @glenn-jocher) 🤸

  • NDJSON pose conversion can now infer missing kpt_shape automatically (when possible), instead of failing immediately.
  • Keeps strict validation for inconsistent or ambiguous keypoint data.

• Docs correctness and usability fixes 📚

  • Fixed broken anchor links in several docs pages (PR #23868).
  • Corrected cfg.md defaults for plots and save to True (PR #23917).
  • Removed outdated TensorRT INT8 “batch doubling” documentation (PR #23911).

• Docs/site maintenance and CI updates 🛠️

  • Updated docs JS dependencies (including chat.js and tablesort) (PR #23908).
  • Added Google Tag Manager to docs template (PR #23776).
  • Migrated print() to centralized LOGGER in docs reference builder (PR #23895).
  • Bumped Slack GitHub Action in workflows from v2.1.1 to v3.0.1 (PR #23910).

🎯 Purpose & Impact

• For users deploying models in different formats 🌍
  This release should improve consistency and stability of inference behavior across backends, with fewer backend-specific surprises.

• For developers and contributors 👩‍💻
  The modular backend design is a big win: easier to extend, debug, and maintain than a monolithic AutoBackend.

• For pose dataset workflows 📦
  NDJSON conversion is more forgiving and practical, reducing friction when metadata is incomplete.

• For documentation trustworthiness ✅
  Multiple fixes make docs more accurate and navigable, reducing confusion around defaults and TensorRT calibration behavior.

Overall, v8.4.23 is a foundational engineering release: not a flashy model change, but a high-impact internal upgrade that strengthens the reliability of the Ultralytics inference stack over time.

What's Changed

• fix broken anchor links in docs by @raimbekovm in #23868
• Update mkdocs.yml chat.js @v0.2.5 by @glenn-jocher in #23908
• replace print() with LOGGER in build_reference.py by @raimbekovm in #23895
• Bump slackapi/slack-github-action from 2.1.1 to 3.0.1 in /.github/workflows by @dependabot[bot] in #23910
• fix incorrect plots and save defaults in cfg.md by @raimbekovm in #23917
• fix outdated INT8 batch doubling references in TensorRT docs by @raimbekovm in #23911
• Infer NDJSON Pose keypoint length by @glenn-jocher in #23921
• Fix shape and type comment bugs in Autobackend and Tuner by @raimbekovm in #23918
• added google tag manager to main.html by @matt-ultralytics in #23776
• ultralytics 8.4.23 Refactor AutoBackend into modular per-backend classes by @Laughing-q in #23790

New Contributors

• @matt-ultralytics made their first contribution in #23776

Full Changelog: v8.4.22...v8.4.23