New Release: Ultralytics v8.4.6

Discussion
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:rocket: Ultralytics v8.4.6 is out — reliability upgrade for DDP + smoother ul:// datasets :hammer_and_wrench::package:

Ultralytics v8.4.6 is a reliability-focused release that fixes a multi-GPU DDP training crash, improves dataset URI handling for larger ul://... datasets, and ships several docs/Platform workflow upgrades :chart_increasing::white_check_mark:
You can review the full details in the Ultralytics v8.4.6 release page.

:white_check_mark: New Features & Key Fixes (high impact)

:control_knobs: Fixed multi-GPU DDP training crash

  • PR: #23301 by @pfabreu
  • What changed: Added a missing PosixPath import to the generated temporary DDP training script (ultralytics/utils/dist.py).
  • Why it matters: Prevents NameError: name 'PosixPath' is not defined when model paths are passed as Path/PosixPath objects during DDP training (common on Linux) :fire_extinguisher::puzzle_piece:

:globe_with_meridians: More robust dataset URI resolution for large ul://... datasets

  • PR: #23305 by @glenn-jocher
  • What changed: ul://... dataset URLs now allow more server-side preparation time (NDJSON generation), reducing premature timeouts on large datasets :turtle::package:

:broom: Improvements (developer quality)

:brain: BYTETracker typing modernized (no behavior change)

  • PR: #23304 by @ahmet-f-gumustas
  • What changed: Migrated legacy # type: comments to inline annotations in byte_tracker.py :wrench:

:books: Docs & Ultralytics Platform guidance updates

:compass: New/updated Platform docs + usability improvements

  • PR: #23294 by @glenn-jocher
  • What changed: Added docs for Activity Feed and Trash/Restore, refreshed billing/GPU pricing, and added “Try on Ultralytics Platform” callouts for YOLO11, YOLO26, YOLOv5, and YOLOv8 :writing_hand::rocket:

:writing_hand: Doc typo fixes (YOLO26 + YOLOE)

:new_button: New contributor shoutout :tada:

:high_voltage: Quick start (upgrade + sanity check)

pip install -U ultralytics
yolo version

If you’re training on multi-GPU, this is a good release to pick up—especially if you hit issues in 8.4.5 with DDP + Path/PosixPath inputs.

:speaking_head: Feedback wanted

Try v8.4.6 and let us know:

  • Did it resolve your DDP multi-GPU crash? :control_knobs:
  • Are your ul://... datasets loading more reliably now? :globe_with_meridians:
  • Anything else you want improved for YOLO26 workflows (detect/segment/classify/pose/OBB)? :rocket: