New Release: Ultralytics v8.3.238

Discussion
, ,
1

:rocket: Ultralytics v8.3.238 is out!

v8.3.238 is a refinement-heavy release focused on making SAM3 concept/video segmentation more robust, faster to work with, and easier to install, while also improving export stability (TFLite/ONNX) plus CI + docs polish. :brain::movie_camera::package:

If you want the full details, jump into the v8.3.238 release page and the full changelog comparison.

:puzzle_piece: New Features & Highlights (SAM3-heavy release)

:brick: SAM3 architecture refactors

  • Shared helper for SAM3 neck feature generation (sam_forward_feature_levels) to reduce duplication and unify multi-scale features + positional encodings.
  • VL combiner + neck now reuse this helper across SAM3 and optional SAM2 paths.
  • SAM3 image/video predictors now share backbone feature prep logic with SAM2 (_prepare_backbone_features) for more consistent multi-prompt batching.

:wrench: SAM3 stability & correctness

  • Batching cache bug fixed: SAM3SemanticPredictor no longer corrupts cached backbone features when querying the same image with different prompt batch sizes (great for “encode once, query many times” workflows).
  • Apple Silicon (MPS) reliability: attention path enforces contiguous tensors and simplifies dtype conversions.
  • Tokenizer deps auto-check/install prompt for semantic/text workflows (ftfy, regex, iopath) to avoid surprise ModuleNotFoundError crashes.
  • Cleaner docstrings + docs aligned to the public API import path: from ultralytics.models.sam import ...

:movie_camera: SAM3 video API & docs improvements

  • Docs now show the simplified import path: from ultralytics.models.sam import SAM3VideoSemanticPredictor
  • Clarified SAM3 sizing/specs and noted SAM3 is fully available since v8.3.237.

:airplane_departure: Export & Deployment Improvements

  • ONNX FP16 guardrails: FP16 conversion now only runs when --half + --format=onnx + device=cpu are all true (prevents cross-format export surprises).
  • TFLite dtype mismatch fix when using half=True with nms=True.
  • MNN export safety: skip slow tests if torch<1.10 and assert minimum torch version to prevent runtime crashes.
  • Clarified onnx pin notes (onnx>=1.12.0,<=1.19.1) until tooling catches up.

:building_construction: CI / Tooling / Infra

  • CI Summary now depends on SlowTests, and Slack alerts trigger on SlowTests failures too (better signal on real regressions).
  • Docker runner image improvements (apt-get update, libicu-dev, cleanup).
  • GitHub Actions artifact uploader bumped actions/upload-artifact v5 → v6 (Node 24 runtime).

:globe_showing_europe_africa: Examples & UX Polish

  • .gitignore now allows examples/**/requirements.txt for demo-specific deps.
  • RT-DETR ONNXRuntime example improvements (safer downloads, validation, optional NMS filter, fixed COCO YAML URL).
  • Interactive tracking UI safer defaults (e.g. save_video=False).

:pushpin: What’s Changed (PRs + Authors)

:new_button: New contributors

:white_check_mark: Try it now

pip install -U ultralytics

If you hit any issues (especially around SAM3, MPS, or export), please share repro steps in a GitHub issue—feedback helps us keep improving for everyone. :raising_hands: