ultralytics 8.4.45

v8.4.45 - `ultralytics 8.4.45` Fix pretrained checkpoint training regression (#24378)

on Python PyPI

🌟 Summary (single-line synopsis)

Ultralytics v8.4.45 is a hotfix release that primarily restores correct pretrained training behavior for .pt models (like YOLO26 checkpoints), plus important TensorRT/Jetson export reliability improvements and clearer docs. 🚀

📊 Key Changes

• 🔥 Critical training hotfix (PR #24378 by @glenn-jocher):

  • Restored default behavior so YOLO("*.pt").train() and CLI training correctly start from pretrained checkpoint weights.
  • pretrained=False now only disables weight loading when explicitly set.
  • Custom pretrained weight paths are preserved.
  • Classification scratch-training reset behavior was restored.
  • Version bumped to 8.4.45.

• ⚙️ TensorRT compatibility hardening:

  • Blocked problematic TensorRT 10.2.0 (replacing older 10.1.0 exclusion) to avoid known runtime/export issues.
  • Unified TensorRT dependency checks using shared check_tensorrt() for more consistent setup.

• 🤖 Jetson / INT8 export improvements (PR #24368):

  • JetPack 6 Docker image now upgrades TensorRT from 10.3 to 10.7 to fix INT8 + end2end build issues.
  • Automatic end2end disable is now scoped to the specific problematic case: JetPack 6 + TensorRT 10.3.0 + INT8.
  • Added clearer warning messaging and troubleshooting docs.

• 📦 Export argument support expanded:

  • Added data as a valid argument for more export formats (including TensorRT, OpenVINO, CoreML, TFLite, TF.js, MNN, IMX), improving dataset-aware INT8/export workflows.

• 📚 Documentation updates:

  • Hyperparameter tuning guide updated to match actual tuner behavior and output formats.
  • New Ultralytics Platform dataset Clustering docs added (interactive 2D exploration for clusters, outliers, duplicates).

🎯 Purpose & Impact

• ✅ Biggest user impact: fixes a regression where training from .pt checkpoints could silently skip pretrained weights, which could reduce accuracy and waste training time.
• 🧠 More predictable training behavior: defaults now work as users expect, while still allowing explicit scratch training via pretrained=False.
• 🛡️ Fewer deployment pitfalls: better TensorRT version guardrails reduce hard-to-debug export/runtime errors.
• 🚀 Better Jetson experience: INT8 export is more reliable on JetPack 6, with a clear upgrade path for full end2end behavior.
• 🧰 Cleaner export workflows: broader data argument support reduces validation friction across backends.
• 📖 Lower confusion: docs now better reflect real behavior, helping both new and advanced users work faster.

What's Changed

• Exclude tensorrt==10.2.0 to fix libnvinfer_builder_resource_win.so.10.2.0 error by @lakshanthad in #24367
• Auto-update tensorrt from 10.3 to 10.7 on JetPack 6 systems to fix YOLO26 int8 build issues by @lakshanthad in #24368
• Update hyperparameter tuning guide to match current tuner behaviour by @raimbekovm in #24372
• Add data argument to valid args for INT8 export formats by @lakshanthad in #24362
• Docs: Datasets Clustering by @sergiuwaxmann in #24376
• ultralytics 8.4.44 Apply pretrained arg across model trainers by @glenn-jocher in #24374
• ultralytics 8.4.45 Fix pretrained checkpoint training regression by @glenn-jocher in #24378

Full Changelog: v8.4.43...v8.4.45