{
 "schema_version": "1.7.0",
 "id": "x_NXMC-2026-0054",
 "modified": "2026-10-19T02:33:38.839Z",
 "published": "2026-10-18T09:00:52.565Z",
 "summary": "Step-3.5-Flash: structural change at ef9cf3c (2026-03-09)",
 "details": "Step-3.5-Flash: derived parameters 8.28B to 8.81B (+528.1M, +1.06 GB of bf16 weights); tie_word_embeddings unset to false; the output head is no longer shared with the embedding (2026-03-09).\n\nRepository: https://huggingface.co/stepfun-ai/Step-3.5-Flash. Revisions from ef9cf3cda3b4d76a67250e6eaa11d6ad7a8f2a73 onward carry this change; a pin at 7eb38d5f01854a401901ea6800bd9328f91a5085 or earlier does not.\n\nChanged keys:\n- tie_word_embeddings: unset -> false (structural)\n\nThis record says what the change does mechanically. It is not a report that anything broke for anyone.",
 "affected": [
  {
   "ranges": [
    {
     "type": "GIT",
     "repo": "https://huggingface.co/stepfun-ai/Step-3.5-Flash",
     "events": [
      {
       "introduced": "ef9cf3cda3b4d76a67250e6eaa11d6ad7a8f2a73"
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   ],
   "database_specific": {
    "model": "stepfun-ai/Step-3.5-Flash",
    "previous_revision": "7eb38d5f01854a401901ea6800bd9328f91a5085"
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 ],
 "references": [
  {
   "type": "INTRODUCED",
   "url": "https://huggingface.co/stepfun-ai/Step-3.5-Flash/commit/ef9cf3cda3b4d76a67250e6eaa11d6ad7a8f2a73"
  },
  {
   "type": "PACKAGE",
   "url": "https://huggingface.co/stepfun-ai/Step-3.5-Flash"
  },
  {
   "type": "WEB",
   "url": "https://www.neurarch.com/changes-feeds/models/stepfun-ai/Step-3.5-Flash.html"
  }
 ],
 "database_specific": {
  "source": "neurarch model change tracker",
  "model": "stepfun-ai/Step-3.5-Flash",
  "kind": "structural",
  "classes": [
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  ],
  "changed_keys": [
   {
    "file": "config",
    "key": "tie_word_embeddings",
    "before": null,
    "after": false,
    "class": "structural"
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  ],
  "impact": {
   "memory": true,
   "serving": true,
   "tokenizer": false,
   "licence": null
  },
  "breaking": true,
  "breaking_rule": "https://www.neurarch.com/changes-feeds/advisories/index.json#breaking_rule",
  "consequence": {
   "params": {
    "before": 8281427968,
    "after": 8809523072
   },
   "weightsGbBf16": {
    "before": 16.563,
    "after": 17.619
   },
   "trainPeakGb": {
    "before": 565.738,
    "after": 623.181
   },
   "fingerprint": {
    "before": "2de5a957",
    "after": "1773acdc"
   },
   "context": null,
   "eos": null,
   "bos": null
  },
  "commit_date": "2026-03-09T03:54:54.000Z",
  "detected_at": "2026-10-18T09:00:52.565Z",
  "detected_by": "backfill",
  "days_since_first_commit": 35,
  "license": "CC-BY-4.0"
 }
}