🌟 Summary (single-line synopsis)

Ultralytics v8.4.6 is a reliability-focused release that fixes a multi-GPU DDP training crash and improves Ultralytics HUB/Platform dataset URI handling, plus several documentation upgrades 📈🛠️

📊 Key Changes

• ✅ Fixed DDP multi-GPU training crash (PR #23301 by @pfabreu)
  • Added missing PosixPath import to the generated temporary DDP training script (ultralytics/utils/dist.py).
  • Prevents NameError: name 'PosixPath' is not defined when model paths are passed as PosixPath objects (common on Linux) during Distributed Data Parallel training 🧩🧯
• ⏱️ More robust dataset URI resolution for large Ultralytics HUB/Platform datasets (PR #23305 by @glenn-jocher)
  • ul://... dataset URLs now allow a much longer server-side preparation time (NDJSON generation) to avoid premature timeouts 🐢📦
• 🧹 Developer quality: BYTETracker typing modernized (PR #23304)
  • Switched legacy # type: comments to inline type annotations in BYTETracker (no behavior change) 🧠🔧
• 📚 Docs + Platform guidance improvements (PR #23294, #23298)
  • Added new docs for Activity Feed and Trash/Restore, refreshed billing/GPU pricing, added “Try on Ultralytics Platform” callouts for YOLO11 / YOLO26 / YOLOv5 / YOLOv8, plus small typo fixes ✍️🚀

🎯 Purpose & Impact

• DDP training is stable again on multi-GPU setups 🎛️✅
  • If you upgraded to 8.4.5 and saw failures when launching DDP training (especially with models like yolo26n.pt passed as a Path/PosixPath), this release removes that blocker—less downtime, fewer confusing crashes.
• Fewer flaky failures when using ul://... datasets from Ultralytics HUB/Platform 🌐✅
  • Large datasets can take longer to prepare; the smarter timeout reduces false “timeout” errors during dataset resolution.
• Better usability and discoverability in docs 🧭📘
  • Clearer Platform workflows (Activity Feed, Trash/Restore) and more direct “try it now” paths for major YOLO models.

For more context, see the v8.4.6 release tag on GitHub.

What's Changed

• Improve Platform docs by @glenn-jocher in https://github.com/ultralytics/ultralytics/pull/23294
• Fix typos in YOLO26 and YOLOE docs by @raimbekovm in https://github.com/ultralytics/ultralytics/pull/23298
• Longer NDJSON generation timeout by @glenn-jocher in https://github.com/ultralytics/ultralytics/pull/23305
• Modernize type comments to inline annotations in byte_tracker.py by @ahmet-f-gumustas in https://github.com/ultralytics/ultralytics/pull/23304
• ultralytics 8.4.6 Add missing PosixPath import in DDP train file gen by @pfabreu in https://github.com/ultralytics/ultralytics/pull/23301

New Contributors

• @ahmet-f-gumustas made their first contribution in https://github.com/ultralytics/ultralytics/pull/23304

Full Changelog: https://github.com/ultralytics/ultralytics/compare/v8.4.5...v8.4.6