v4.0.0a1

What's Changed

• 3.0 CI Bugs by @jlarson4 in #1261
• fix: use cfg.dtype instead of torch.get_default_dtype for KV cache init by @davidcyze in #1260
• Fix tests broken by a local GPU by @brendanlong in #1219
• fix: handle LayerNorm folding correctly in load_and_process_state_dict by @VedantMadane in #1215
• Fix HookedTransformerConfig rotary_base types by @brendanlong in #1231
• Fixed Masking in HookedTransformer.generate by @tuomaso in #999
• Add hooked transformer generate stream by @anthonyduong9 in #908
• Add py.typed for type hints by @UFO-101 in #760
• Created Baichuan Architecture adapter by @jlarson4 in #1262
• Make FactoredMatrix compatible with tensor-like arguments by @JasonGross in #599
• NanoGPT Conversation did not handle case when there were no biases in model by @dashstander in #629
• [BUG] Batched Generation solution extended to run_with_cache and run_with_hooks for TransformerBridge by @jlarson4 in #1265
• Added 1D tensor handling to TransformerBridge by @jlarson4 in #1266
• Added n_ctx override to TransformerBridge by @jlarson4 in #1269
• Feature/generate stream on bridge by @jlarson4 in #1268
• Added warnings for users attempting to use MPS with Torch 2.8 by @jlarson4 in #1271
• Improved Tokenize & Concatenate by @jlarson4 in #1273
• Multi-Device Processing on Bridge by @jlarson4 in #1270
• Adding Architecture Adapter Creation Guide to Docs by @jlarson4 in #1274
• Fixed Quantization bug in TransformerLens 3.0 by @jlarson4 in #1276
• Fix generate() when tokenizer is unset and add regression tests by @DityaChawla in #1267
• Updated boot_transformers to use local hf_config, if provided by @jlarson4 in #1279
• Prevent weight processing split between devices by @jlarson4 in #1281
• Fix: IOIDataset generates diverse samples by @DivijChawla in #1282
• Fix: preserve tokenizer.padding_side when reloading with add_bos_token by @DivijChawla in #1283
• MPS CI Support by @huseyincavusbi in #1278
• Add n_params_total property for total parameter count by @DivijChawla in #1284
• Model Table Cleanup by @jlarson4 in #1285
• Demos/bridge lm eval demo by @jlarson4 in #1286
• Tokenize and Concatenate additional datasets by @jlarson4 in #1287
• Resolution to Issues #477 and #264 by @jlarson4 in #1288
• mT5 Support by @jlarson4 in #1289
• SimpleStories Model verification by @jlarson4 in #1292
• Verification System Improvements by @jlarson4 in #1293
• fix: Bump CI actions and stabilize flaky notebook checks by @huseyincavusbi in #1290
• Fix bridge generate with no tokenizer by @jlarson4 in #1299
• Issue resolution for #341, #644, and #210 by @jlarson4 in #1300
• Resolution for #796, #453, #385, and #297 by @jlarson4 in #1301
• Improve Architecture Adapter Testing by @jlarson4 in #1303
• Resolution for #112 and #830 by @jlarson4 in #1304
• Add OPT architecture adapter tests by @willytop8 in #1305
• Add GPT2 and Gpt2LM Head architecture adapter tests by @sunny1401 in #1306
• Qwen3.5 text-only TransformerBridge support by @SamuelePunzo in #1313
• Add GPT-J architecture adapter tests by @along-l in #1314
• Feat/external architecture registration by @huseyincavusbi in #1307
• Transformers v5 Gemma scaling adjustment by @jlarson4 in #1315
• Adding adapter tests for Qwen2 by @Rishik00 in #1309
• HuggingFace Rate Limit Improvements by @jlarson4 in #1318
• Compatibility Mode – pre-ln split qkv hooks by @jlarson4 in #1319
• Pre-release cleanup by @jlarson4 in #1320
• Add Mixtral architecture adapter tests by @RecreationalMath in #1329
• Removed unused PythiaArchitectureAdapter from TransformerLens by @Rishik00 in #1332
• Add qwen3 and llava_next adapter tests by @sunny1401 in #1331
• Feature/telemetry demo notebook by @jonathanrbelanger-lang in #1308
• Add OLMoE architecture adapter tests by @RecreationalMath in #1333
• Test coverage/cleaning up xfails by @jlarson4 in #1334
• Initial Driver System by @jlarson4 in #1335
• vLLM Batches by @jlarson4 in #1338
• Add return_cache option to TransformerBridge.generate by @RecreationalMath in #1337
• Fix FactoredMatrix indexing returning empty result for -1 index by @Kymi808 in #1340
• Add GPT-OSS architecture adapter tests by @RecreationalMath in #1341
• vLLM Driver Bugs by @jlarson4 in #1343
• Remove deprecated move_model parameter from ActivationCache.to by @RecreationalMath in #1344
• Fix run_with_cache(device=...) permanently moving the model by @RecreationalMath in #1345
• Fix to_numpy() crash on bfloat16 tensors by upcasting to float32 by @robbiebusinessacc in #1346
• Fix sample_logits crash when top_k exceeds vocab size by @robbiebusinessacc in #1347
• Update broken Slack link again by @APatelUIUC in #1339

New Contributors

• @davidcyze made their first contribution in #1260
• @VedantMadane made their first contribution in #1215
• @tuomaso made their first contribution in #999
• @dashstander made their first contribution in #629
• @DityaChawla made their first contribution in #1267
• @DivijChawla made their first contribution in #1282
• @willytop8 made their first contribution in #1305
• @sunny1401 made their first contribution in #1306
• @along-l made their first contribution in #1314
• @Rishik00 made their first contribution in #1309
• @RecreationalMath made their first contribution in #1329
• @jonathanrbelanger-lang made their first contribution in #1308
• @Kymi808 made th...

v3.3.0

What's Changed

transformers version bumped to 5.4.0 This should not negatively effect existing users, the pyproject.toml was resolving to >5.4.0 already and the dependency update was required to properly support Qwen 3.5

• fix: Bump CI actions and stabilize flaky notebook checks by @huseyincavusbi in #1290
• Fix bridge generate with no tokenizer by @jlarson4 in #1299
• Issue resolution for #341, #644, and #210 by @jlarson4 in #1300
• Resolution for #796, #453, #385, and #297 by @jlarson4 in #1301
• Improve Architecture Adapter Testing by @jlarson4 in #1303
• Resolution for #112 and #830 by @jlarson4 in #1304
• Add OPT architecture adapter tests by @willytop8 in #1305
• Add GPT2 and Gpt2LM Head architecture adapter tests by @sunny1401 in #1306
• Qwen3.5 text-only TransformerBridge support by @SamuelePunzo in #1313
• Add GPT-J architecture adapter tests by @along-l in #1314
• Feat/external architecture registration by @huseyincavusbi in #1307
• Transformers v5 Gemma scaling adjustment by @jlarson4 in #1315
• Adding adapter tests for Qwen2 by @Rishik00 in #1309
• HuggingFace Rate Limit Improvements by @jlarson4 in #1318
• Compatibility Mode – pre-ln split qkv hooks by @jlarson4 in #1319
• Pre-release cleanup by @jlarson4 in #1320
• Fix TransformerBridge backward hook cleanup by @SamuelePunzo in #1324
• Add Mixtral architecture adapter tests by @RecreationalMath in #1329
• Removed unused PythiaArchitectureAdapter from TransformerLens by @Rishik00 in #1332
• Add qwen3 and llava_next adapter tests by @sunny1401 in #1331
• Feature/telemetry demo notebook by @jonathanrbelanger-lang in #1308
• Add OLMoE architecture adapter tests by @RecreationalMath in #1333
• Test coverage/cleaning up xfails by @jlarson4 in #1334
• Release 3.3.0 by @jlarson4 in #1321

New Contributors

• @willytop8 made their first contribution in #1305
• @sunny1401 made their first contribution in #1306
• @SamuelePunzo made their first contribution in #1313
• @along-l made their first contribution in #1314
• @Rishik00 made their first contribution in #1309
• @jonathanrbelanger-lang made their first contribution in #1308

Full Changelog: v3.2.1...v3.3.0

v3.2.1

What's Changed

Hot fix for issues with Gemma3 multimodal interp.

• Release v3.2.1 by @jlarson4 in #1295

Full Changelog: v3.2.0...v3.2.1

v3.2.0

What's Changed

• Fix generate() when tokenizer is unset and add regression tests by @DityaChawla in #1267
• Updated boot_transformers to use local hf_config, if provided by @jlarson4 in #1279
• Prevent weight processing split between devices by @jlarson4 in #1281
• Fix: IOIDataset generates diverse samples by @DivijChawla in #1282
• Fix: preserve tokenizer.padding_side when reloading with add_bos_token by @DivijChawla in #1283
• MPS CI Support by @huseyincavusbi in #1278
• Add n_params_total property for total parameter count by @DivijChawla in #1284
• Model Table Cleanup by @jlarson4 in #1285
• Demos/bridge lm eval demo by @jlarson4 in #1286
• Tokenize and Concatenate additional datasets by @jlarson4 in #1287
• Resolution to Issues #477 and #264 by @jlarson4 in #1288
• mT5 Support by @jlarson4 in #1289
• SimpleStories Model verification by @jlarson4 in #1292
• Verification System Improvements by @jlarson4 in #1293
• Release v3.2.0 by @jlarson4 in #1294

New Contributors

• @DityaChawla made their first contribution in #1267
• @DivijChawla made their first contribution in #1282

Full Changelog: v3.1.0...v3.2.0

v3.1.0

What's Changed

• 3.0 CI Bugs by @jlarson4 in #1261
• fix: use cfg.dtype instead of torch.get_default_dtype for KV cache init by @davidcyze in #1260
• Fix type of HookedTransformerConfig.device by @brendanlong in #1230
• Fix tests broken by a local GPU by @brendanlong in #1219
• fix: handle LayerNorm folding correctly in load_and_process_state_dict by @VedantMadane in #1215
• Fix HookedTransformerConfig rotary_base types by @brendanlong in #1231
• Fixed Masking in HookedTransformer.generate by @tuomaso in #999
• Add hooked transformer generate stream by @anthonyduong9 in #908
• Add py.typed for type hints by @UFO-101 in #760
• Created Baichuan Architecture adapter by @jlarson4 in #1262
• Make FactoredMatrix compatible with tensor-like arguments by @JasonGross in #599
• NanoGPT Conversation did not handle case when there were no biases in model by @dashstander in #629
• [BUG] Batched Generation solution extended to run_with_cache and run_with_hooks for TransformerBridge by @jlarson4 in #1265
• Added 1D tensor handling to TransformerBridge by @jlarson4 in #1266
• Added n_ctx override to TransformerBridge by @jlarson4 in #1269
• Feature/generate stream on bridge by @jlarson4 in #1268
• Added warnings for users attempting to use MPS with Torch 2.8 by @jlarson4 in #1271
• Improved Tokenize & Concatenate by @jlarson4 in #1273
• Multi-Device Processing on Bridge by @jlarson4 in #1270
• Adding Architecture Adapter Creation Guide to Docs by @jlarson4 in #1274
• Fixed Quantization bug in TransformerLens 3.0 by @jlarson4 in #1276
• TransformerLens 3.1.0 by @jlarson4 in #1277

New Contributors

• @davidcyze made their first contribution in #1260
• @VedantMadane made their first contribution in #1215
• @tuomaso made their first contribution in #999
• @dashstander made their first contribution in #629

Full Changelog: v3.0.0...v3.1.0

TransformerLens 3.0

What's Changed

Migrating to a new way to implement models via the TransformerBridge system. Increased model support from ~200 models to ~9,000 models

• Refactor the utilities file into utilities folder by @starship006 in #628
• Raise exception when BERT is loaded with HookedTransformer instead of… by @degenfabian in #795
• Circular dependency resolution by @bryce13950 in #803
• fixed corner param by @bryce13950 in #817
• bumped python min version by @bryce13950 in #802
• Updates torch to use the most recent version by @bryce13950 in #822
• updated python requirements by @bryce13950 in #821
• Recent releases by @bryce13950 in #841
• updated mypy limit by @bryce13950 in #880
• Activation utils cleanup by @bryce13950 in #879
• Restore consistency of hook_normalized between LayerNorm and RMSNorm by @degenfabian in #770
• Fix that padding_side always defaults to "right" when no value is explicitly passed by @degenfabian in #814
• Unified conversions by @bryce13950 in #881
• Flatten state dictionary for proper weight loading by @degenfabian in #860
• enabled actions on action pr by @bryce13950 in #882
• Add weight conversion for Phi model by @degenfabian in #863
• Add weight conversion for T5 models by @degenfabian in #859
• Visualize weight conversions by @degenfabian in #852
• Fixed test for ensuring weight conversions are provided by @bryce13950 in #883
• Drop python 3.9 by @bryce13950 in #885
• Conversion improved test coverage by @bryce13950 in #886
• Component test coverage by @bryce13950 in #890
• Bug new loading by @bryce13950 in #891
• Weight conversion llama by @bryce13950 in #892
• Refactor supported models module by @bryce13950 in #893
• Bug neox by @bryce13950 in #895
• Feature model adapter by @bryce13950 in #928
• added test for making sure formatting works well by @bryce13950 in #932
• Refactor final issues by @bryce13950 in #933
• restored tokenizer content by @bryce13950 in #935
• Refactor weight conversion by @bryce13950 in #931
• added python 3.13 to CI by @bryce13950 in #843
• upstream fixes from dev by @bryce13950 in #941
• Flexible component mapping by @bryce13950 in #938
• Move flatten dictionary to architecture_conversion by @degenfabian in #936
• made new transformer bridge extend nn module properly by @bryce13950 in #955
• brought in remaining hooked transformer functions by @bryce13950 in #954
• Setup tokenizer in boot function by @degenfabian in #959
• Bridged Robust Model Structure by @bryce13950 in #960
• Remove transformers dependency from bridge tokenization by @degenfabian in #963
• Dynamically add boot function to bridge by @degenfabian in #964
• Pre release version publishing by @bryce13950 in #973
• Setup deprecated hook aliases and got the majority of the main demo running properly by @bryce13950 in #976
• Linear test coverage by @bryce13950 in #977
• Create Bridge for every Gemma 3 module by @degenfabian in #966
• Add Bridges for every module in GPT2 by @degenfabian in #967
• Cache hook aliases & stop at layer by @bryce13950 in #978
• Create Bridges for every module in Bloom models by @degenfabian in #970
• Create Bridges for every module in Gemma 2 by @degenfabian in #971
• Create bridges for every module in Gemma 1 by @degenfabian in #972
• Create bridges for every module in Mistral by @degenfabian in #979
• Remove that output_attention flag defaults to true in boot function by @degenfabian in #982
• Create bridge for every module in GPT-J by @degenfabian in #974
• Create bridge for every module in Llama by @degenfabian in #975
• Unified aliases by @bryce13950 in #991
• fixed hook alias positions by @bryce13950 in #992
• Create bridge for every module in Mixtral by @degenfabian in #984
• removed numpy ceiling by @bryce13950 in #994
• Ensure hook and property backwards compatibility with HookedTransformer by @degenfabian in #990
• Create bridge for every module in neox by @degenfabian in #995
• Create bridges for every module in neo by @degenfabian in #987
• Weight conversion renaming by @bryce13950 in #996
• Attention shape normalization by @bryce13950 in #997
• Joint hook handling by @bryce13950 in #1001
• Add compatibility_mode feature by @degenfabian in #998
• Add support for GPT-OSS by @degenfabian in #1004
• Fix GPT-OSS initialization error by @degenfabian in #1007
• added setters and hook utils to bridge by @bryce13950 in #1009
• updated property access by @bryce13950 in #1026
• feat: Bridge.boot should allow using alias model names, but show a deprecation warning by @hijohnnylin in #1028
• Move QKV separation into bridge that wraps QKV matrix by @degenfabian in #1027
• removed unnecessary import by @bryce13950 in #1030
• Attn pattern shape by @bryce13950 in #1029
• added cache layer for hook collection by @bryce13950 in #1032
• Bridge unit test compatibility coverage by @bryce13950 in #1031
• updated loading in interactive neuroscope demo to use transformer bridge by @degenfabian in #1017
• map hook_pos_embed to rotary_emb, allow hook_aliases to be a list by @hijohnnylin in #1034
• created new base config class by @bryce13950 in #1042
• made sure to check for nested hooks by @bryce13950 in #1035
• Fix warning for aliases when compatibility mode is turned off by @degenfabian in #1041
• Feature kv cache by @bryce13950 in https...

v2.18.0

What's Changed

• Isolate demo dependencies and pin orjson for CVE-2025-67221 mitigation by @evcyen in #1173
• feat: Add LIT integration for interactive model analysis (#121) by @HetanshWaghela in #1163
• fix: set n_ctx=512 for TinyStories models by @puranikyashaswin in #1162
• Fix/tokenize and concatenate invalid token by @evcyen in #1179
• Remove spurious warning for tokenize_and_concatenate by @evcyen in #1177
• Add MMLU benchmark evaluation to evals by @CarlG0123 in #1183
• Fix/1076 logit lens layer norm by @evcyen in #1180
• Updating Interactive Neuroscope, CI to properly install demo by @jlarson4 in #1205
• Fix tokenize_and_concatenate splitting tokens across chunk boundaries by @brainsnog in #1201
• Fix deprecated IPython magic() calls in demo notebooks (issue #1036) by @brainsnog in #1203
• Expose n_ctx override in HookedTransformer.from_pretrained (issue #1006) by @brainsnog in #1204
• Added warning flags for usages of MPS by @jlarson4 in #1182
• Add GPT-OSS-20B model support by @CarlG0123 in #1195
• fixed the logit lens implementation inside ActivationCache.accumulated_resid to match the standard definition in literature and the expected and defined behavior as per the documentation in the docstring and in the docs by @hartigel in #1077
• Add Apertus model support with XIeLU activation by @sinievanderben in #1197
• Fix attention calculation on mps for torch 2.8.0 by @BrownianNotion in #1068
• HuBERT support rollout by @david-wei-01001 in #1111
• Pre-release testing by @jlarson4 in #1210
• Fix backward hooks Runtime Error by @evcyen in #1175
• Release v2.18.0 by @jlarson4 in #1211

New Contributors

• @evcyen made their first contribution in #1173
• @HetanshWaghela made their first contribution in #1163
• @puranikyashaswin made their first contribution in #1162
• @CarlG0123 made their first contribution in #1183
• @brainsnog made their first contribution in #1201
• @hartigel made their first contribution in #1077
• @sinievanderben made their first contribution in #1197
• @BrownianNotion made their first contribution in #1068
• @david-wei-01001 made their first contribution in #1111

Full Changelog: v2.17.0...v2.18.0

v3.0.0b3

What's Changed

• Support callable filters in TransformerBridge.add_hook() by @jlarson4 in #1186
• Update Patching Hook to avoid causing conflicts by @jlarson4 in #1187
• Prevent Stale Joint QKV values from being incorporated into weight folding after Layer Norm application by @jlarson4 in #1188
• Updated to remove hardcoded .cpu() processing by @jlarson4 in #1189
• Return true initial batch size information by @jlarson4 in #1190
• hook_result & Hook Aliases issues by @jlarson4 in #1191
• updated loading in exploratory analysis demo to use transformer bridge by @degenfabian in #1014
• updated loading in patchscopes generation demo to use transformer bridge by @degenfabian in #1021
• Additional Exploratory analysis Demo fixes by @jlarson4 in #1192
• update loading in bert demo to use transformer bridge by @degenfabian in #1015
• updating loading in qwen demo to use transformer bridge by @degenfabian in #1025
• updated loading in activation patching demo to use transformer bridge by @degenfabian in #1011
• updating loading in t5 demo to use transformer bridge by @degenfabian in #1022
• updated loading in attribution patching demo to use transformer bridge by @degenfabian in #1013
• v3.0.0b3 – Notebook Demo Update & Bug Fixes by @jlarson4 in #1196
• Verifying Additional Models by @jlarson4 in #1199
• Feature/multimodal architecture adapters by @jlarson4 in #1200
• Fix boolean 4D attention-mask handling in joint-QKV bridge attention reconstruction by @speediedan in #1198
• Feature/llava next and onevision variants by @jlarson4 in #1202

Full Changelog: v3.0.0b2...v3.0.0b3

v3.0.0b2

What's Changed

• Release 2.16 by @bryce13950 in #945
• Release 2.16.1 by @bryce13950 in #952
• Update README.md by @jmole in #957
• improve model properties table in docs by @mivanit in #769
• Release v2.16.2 by @bryce13950 in #958
• Add Gemma 3 and MedGemma model support by @huseyincavusbi in #1149
• Add timestamp for 2.0 announcement [docs] by @MattAlp in #983
• Add support for Qwen/Qwen3-0.6B-Base model by @mtaran in #1075
• Repairing tests that were failing due to recent contributions by @jlarson4 in #1157
• Fix 934 by @kapedalex in #1155
• Fix 1130 and 1102 by @kapedalex in #1154
• Fix key and value heads patching for models with different n_heads from n_key_value_heads by @nikolaystanishev in #981
• updating the compatibility notebook by @jlarson4 in #1158
• New Release – v2.17.0 by @jlarson4 in #1159
• Integrate v2.17.0 phase1 by @jlarson4 in #1166
• transformers v5 support by @jlarson4 in #1167
• Improve TransformerBridge optimizer compatibility via dual PyTorch/TransformerLens parameter access API by @speediedan in #1143
• Add HuggingFace ModelOutput support to TransformerLens generation API by @speediedan in #1144
• Testing R1 Distills to confirm functional in TransformerLens by @jlarson4 in #1168
• StableLM Architecture Adapter by @jlarson4 in #1171
• Complete type checking for OLMo support (builds on #816) by @taziksh in #1081
• Olmo3 support by @etomoscow in #1170
• Setup and tested OLMo architecture adapters by @jlarson4 in #1174
• Isolate demo dependencies and pin orjson for CVE-2025-67221 mitigation by @evcyen in #1173
• feat: Add LIT integration for interactive model analysis (#121) by @HetanshWaghela in #1163
• OpenELM Architecture Adapter by @jlarson4 in #1172
• fix: set n_ctx=512 for TinyStories models by @puranikyashaswin in #1162
• Architecture Benchmarks – Review & Extension by @jlarson4 in #1176
• created initial model registry tool by @bryce13950 in #1151
• Initial Verification Run by @jlarson4 in #1181
• Additional Verification by @jlarson4 in #1184
• Prepping for v3.0.0b2 by @jlarson4 in #1185

New Contributors

• @jmole made their first contribution in #957
• @huseyincavusbi made their first contribution in #1149
• @MattAlp made their first contribution in #983
• @mtaran made their first contribution in #1075
• @kapedalex made their first contribution in #1155
• @nikolaystanishev made their first contribution in #981
• @taziksh made their first contribution in #1081
• @etomoscow made their first contribution in #1170
• @HetanshWaghela made their first contribution in #1163
• @puranikyashaswin made their first contribution in #1162

Full Changelog: v3.0.0b1...v3.0.0b2

v2.17.0

We've got an exciting new release that includes several new models! Gemma 3, MedGemma, and Qwen3-0.6B-Base are now included in options for models. In addition to these new models, a handful of bugs and other small non-breaking changes were made.

What's Changed

• Update README.md by @jmole in #957
• improve model properties table in docs by @mivanit in #769
• Release v2.16.2 by @bryce13950 in #958
• Add Gemma 3 and MedGemma model support by @huseyincavusbi in #1149
• Add timestamp for 2.0 announcement [docs] by @MattAlp in #983
• Add support for Qwen/Qwen3-0.6B-Base model by @mtaran in #1075
• Repairing tests that were failing due to recent contributions by @jlarson4 in #1157
• Fix 934 by @kapedalex in #1155
• Fix 1130 and 1102 by @kapedalex in #1154
• Fix key and value heads patching for models with different n_heads from n_key_value_heads by @nikolaystanishev in #981
• updating the compatibility notebook by @jlarson4 in #1158
• New Release – v2.17.0 by @jlarson4 in #1159

New Contributors

• @jmole made their first contribution in #957
• @huseyincavusbi made their first contribution in #1149
• @MattAlp made their first contribution in #983
• @mtaran made their first contribution in #1075
• @kapedalex made their first contribution in #1155
• @nikolaystanishev made their first contribution in #981

Full Changelog: v2.16.1...v2.17.0