onnx 1.21.0 on Python PyPI

ONNX v1.21.0 is now available with exciting new features! We would like to thank everyone who contributed to this release!
Please visit onnx.ai to learn more about ONNX and associated projects.

What's Changed

Breaking Changes and Deprecations

Remove defunct model hub integration by @andife in #7678

Spec and Operator

Revert opset 25 version bump by @titaiwangms in #7441
Add 2 bit support to onnx by @vraspar in #7446
Bump opset version to 26 by @titaiwangms in #7469
Remove enforcement to node determinism attribute by @titaiwangms in #7473
Export functions by @cyyever in #7505
[Reland] Cumulative Product Operator by @titaiwangms in #7400
Fix Div integer semantics to use trunc division by @MagellaX in #7585
Clarify DFT behavior when inverse=True and onesided=True (irfft) by @simonbyrne in #7574
Specify 0/0 case in LpNormalization by @titaiwangms in #7618
Clarify NonMaxSuppression IoU threshold uses strict comparison by @Copilot in #7619
Relax model domain requirement from MUST to SHOULD by @Copilot in #7668
Add BitCast operator for bitwise type reinterpretation by @Copilot in #7527

Reference Implementation

Fix CenterCropPad: compare target shape with dimension, not axis index by @Copilot in #7522
Vectorize sigmoid op implementation by @justinchuby in #7556
Fixing verbose logging error at verbose=3 for reference_evaluator by @rothej in #7597
Clean up reference evaluator tests by @VedantMadane in #7684

Utilities and Tools

Add version check for test_executable_permission_check by @andife in #7511
Fix index out of bounds in version converter adapters by @rothej in #7493
Fix default attribute values in shape inference by @matteosal in #7602
Fix Softmax-family shape inference for scalar inputs by @MagellaX in #7625
Fix/merge models value info by @MagellaX in #7608
Add version converter adapters for opset 15, 16, 17, 18 by @alexkvitkevich in #7677
shape_inference: Validate expected size of scalar tensor in ParseData by @skottmckay in #7675

Build, CI and Tests

Force labels in PRs by @titaiwangms in #7442
Fix reuse by @andife in #7463
Change precedence from 'aggregate' to 'override' for generating scripts by @andife in #7458
a) 3.14-dev -> 3.14, b) reduce template injection thread by @andife in #7461
Export register functions by @cyyever in #7496
Fix Python executable detection in virtual environments by @aoguntayo in #7485
Merged Release Workflows for Windows by @Raghul-M in #7509
Bump nanobind to 2.10.2 by @cyyever in #7479
Fix freebsd build by @cyyever in #7518
Revert ONNX CMake changes by @cyyever in #7515
Export functions used in PyTorch by @cyyever in #7524
Export protobuf symbols by @cyyever in #7525
Fix CMAKE_ARGS parsing for windows compatibility by @hmaarrfk in #7532
Replace deprecated github action "test-results-action" by @andife in #7552
Wheels for python 3.14t by @andife in #7558
Clarify permissions comment and update dependencies install by @andife in #7577
Disable credential persistence in checkout action by @andife in #7578
Update create_release.yml, different label options by @andife in #7081
Fix "code injection via template expansion" (build mode in workflow) by @andife in #7584
Add GitHub Actions workflow for dependency review by @andife in #7579
Simplify conditions in workflow by @andife in #7588
Add renovate for updating docker images by @andife in #7572
CMake: improve nanobind discovery for offline builds by @MagellaX in #7530
Build option for OpenSSF Compiler Hardening Flags by @andife in #7601
Improve debugging for pr_checks by @andife in #7623
Fixes pr checks by @andife in #7630
improve condition in github workflows by @andife in #7658
Add ONNX_INSTALL option to disable CMake installations by @Shadows-of-Fire in #7653
fix windows build ; upload by @andife in #7727
Update VERSION_NUMBER to rc4 by @andife in #7759
Update VERSION_NUMBER to final release version by @andife in #7772

Documentation

Update RELEASE-MANAGEMENT.md (time for release cut 1.21) by @andife in #7466
Update rc version publish process by @andife in #7440
Fix typos by @cyyever in #7478
Clarify numpy version dependencies in requirements by @andife in #7488
Add license information to check_pr_label.yml by @andife in #7489
Deduplicate operator doc strings to reduce binary size by @MagellaX in #7531
Clean up reference evaluator tests (#7098) by @sumit2303 in #7654
fix wrong cmake version in Update RELEASE-MANAGEMENT.md by @andife in #7662
Revise security vulnerability reporting guidelines by @andife in #7674
update version in main for next release and also add missing version … by @Sunny-Anand in #7680
[Cherry-Pick] Merge commits from main for security fixes by @Sunny-Anand in #7688
update release branch version to 1.21.0rc1 by @Sunny-Anand in #7714
Cherry pick commits into the release branch by @Sunny-Anand in #7718
update release to rc2 by @Sunny-Anand in #7732
Cherry pick commit by @Sunny-Anand in #7740
update version to rc3 by @Sunny-Anand in #7743

Other Changes

Bump main to v1.21.0 by @titaiwangms in #7437
Bump ruff from 0.13.3 to 0.14.3 by @dependabot[bot] in #7447
Bump actions/github-script from 7 to 8 by @dependabot[bot] in #7452
Bump actions/upload-artifact from 4.6.2 to 5.0.0 by @dependabot[bot] in #7457
Bump actions/download-artifact from 5.0.0 to 6.0.0 by @dependabot[bot] in #7451
Bump reviewdog/action-cpplint from 1.10.0 to 1.11.0 by @dependabot[bot] in #7456
Bump reviewdog/action-misspell from 1.26.3 to 1.27.0 by @dependabot[bot] in #7449
Bump prefix-dev/setup-pixi from 0.9.1 to 0.9.2 by @dependabot[bot] in #7455
Bump editorconfig-checker from 3.4.0 to 3.4.1 by @dependabot[bot] in #7448
Bump stefanzweifel/git-auto-commit-action from 6.0.1 to 7.0.0 by @dependabot[bot] in #7450
Bump fsfe/reuse-action from 5.0.0 to 6.0.0 by @dependabot[bot] in #7453
Bump github/codeql-action from 3.30.6 to 4.31.2 by @dependabot[bot] in #7454
supply chain security => adapt dependabot.yml by @andife in #7459
Add persist-credentials option to checkout action by @andife in #7460
Enable conversion from DataTypeSet into set[str] by @cyyever in #7481
Update entrypoint.sh for improved syntax and checks by @andife in #7483
Require ml_dtypes>=0.5.4 on s390x by @stliibm in #7484
Fix cpplint warnings by @cyyever in #7482
Remove empty line from requirements.txt by @andife in #7492
Add copyright and SPDX license to workflow by @andife in #7490
Bump ruff from 0.14.3 to 0.14.6 by @dependabot[bot] in #7501
Bump actions/checkout from 5.0.0 to 6.0.0 by @dependabot[bot] in #7500
Bump zizmorcore/zizmor-action from 0.2.0 to 0.3.0 by @dependabot[bot] in #7499
Bump ZedThree/clang-tidy-review from 0.21.0 to 0.22.2 by @dependabot[bot] in #7497
Bump clang-format from 21.1.2 to 21.1.6 by @dependabot[bot] in #7503
Bump types-protobuf from 6.30.2.20250822 to 6.32.1.20250918 by @dependabot[bot] in #7353
Add sanity checks for CLI arguments in entrypoint.sh by @andife in #7491
Bump prefix-dev/setup-pixi from 0.9.2 to 0.9.3 by @dependabot[bot] in #7498
Add a tool to dump ONNX schema into yaml files by @cyyever in #7480
More clang-tidy fixes by @cyyever in #7486
Bump actions/checkout from 6.0.0 to 6.0.1 by @dependabot[bot] in #7542
Bump actions/stale from 10.1.0 to 10.1.1 by @dependabot[bot] in #7545
Bump github/codeql-action from 4.31.2 to 4.31.9 by @dependabot[bot] in #7543
Bump actions/upload-artifact from 5.0.0 to 6.0.0 by @dependabot[bot] in #7548
Bump actions/download-artifact from 6.0.0 to 7.0.0 by @dependabot[bot] in #7541
Bump actions/setup-python from 6.0.0 to 6.1.0 by @dependabot[bot] in #7547
Bump codecov/codecov-action from 5.5.1 to 5.5.2 by @dependabot[bot] in #7544
Bump ZedThree/clang-tidy-review from 0.22.2 to 0.22.3 by @dependabot[bot] in #7546
Bump stefanzweifel/git-auto-commit-action from 7.0.0 to 7.1.0 by @dependabot[bot] in #7549
Bump mypy from 1.18.2 to 1.19.1 by @dependabot[bot] in #7540
Bump clang-format from 21.1.6 to 21.1.8 by @dependabot[bot] in #7538
Bump ruff from 0.14.6 to 0.14.10 by @dependabot[bot] in #7537
remove cpplint rule "-readability/todo" from lint.yml by @andife in #7554
Fix cpplint copyright warnings by @andife in #7553
Update pixi.lock file by @cbourjau in #7555
Update RELEASE-MANAGEMENT.md by @andife in #7559
fix possible "code injection via template expansion" by @andife in #7576
More tidy fixes by @cyyever in #7519
Fix zizmor findings by @andife in #7581
Improve lint and cpplint fixes by @andife in #7583
Create release-verification.md by @andife in #7595
Update renovate config by @andife in #7600
Keep non-tensor type information in IR by @take-cheeze in #7592
Fix create_releases.yml by @andife in #7605
Ignore .pb files from github language classification by @justinchuby in #7606
lint copyright header by @andife in #7611
IR: Add API to generate unique name for consistency by @take-cheeze in #7609
Update RELEASE-MANAGEMENT.md by @andife in #7613
Fix pr_checks by @andife in #7607
add missing includes (cpplint highlighted) by @andife in #7621
Fix cpplint warnings by @cyyever in #7622
fix cpplint findings by @andife in #7624
Checks a filename is not a symlink by @xadupre in #7628
Rename pr_checks_comment.yml to pr_checks_post.yml by @andife in #7632
Bump ZedThree/clang-tidy-review from 0.22.3 to 0.23.0 by @dependabot[bot] in #7638
Bump actions/setup-python from 6.1.0 to 6.2.0 by @dependabot[bot] in #7641
Bump actions/checkout from 6.0.1 to 6.0.2 by @dependabot[bot] in #7637
Bump actions/download-artifact from 4.1.9 to 7.0.0 by @dependabot[bot] in #7640
Bump editorconfig-checker from 3.4.1 to 3.6.0 by @dependabot[bot] in #7636
Bump zizmorcore/zizmor-action from 0.3.0 to 0.4.1 by @dependabot[bot] in #7639
Bump actions/upload-artifact from 4.6.1 to 6.0.0 by @dependabot[bot] in #7642
Bump ruff from 0.14.10 to 0.14.14 by @dependabot[bot] in #7635
Bump types-protobuf from 6.32.1.20250918 to 6.32.1.20251210 by @dependabot[bot] in #7539
Fix wrong use of compile options introduced for hardening (Update Utils.cmake) by @andife in #7633
RFC template for large proposals by @cbourjau in #7594
Fix cpplint warnings by @cyyever in #7626
Verifies an external file is valid when saving an external tensor by @xadupre in #7627
Apply C++17 features and remove ANDROID in onnx/string_utils.h by @cyyever in #7649
fix cpplint issues by @andife in #7650
remove thirdparty by @andife in #7655
Add Copyright Header by @andife in #7656
Update CODEOWNERS by @andife in #7669
Update release logistics instructions in OnnxReleases.md by @andife in #7676
IR: Fix use after free in eraseInitializerAndInput by @take-cheeze in #7614
[rel-1.21.0] Cherry-pick bug and security fixes for RC4 (#7737, #7751) by @Sunny-Anand in #7758

New Contributors

@vraspar made their first contribution in #7446
@aoguntayo made their first contribution in #7485
@Raghul-M made their first contribution in #7509
@hmaarrfk made their first contribution in #7532
@rothej made their first contribution in #7493
@MagellaX made their first contribution in #7531
@simonbyrne made their first contribution in #7574
@sumit2303 made their first contribution in #7654
@alexkvitkevich made their first contribution in #7677
@VedantMadane made their first contribution in #7684

Full Changelog: v1.20.1...v1.21.0

onnx 1.21.0 v1.21.0 on Python PyPI