{
 "schema_version": "1.7.0",
 "id": "x_NXMC-2024-0119",
 "modified": "2026-10-19T02:33:38.839Z",
 "published": "2026-10-18T09:00:52.565Z",
 "summary": "Qwen2.5-1.5B: tokenizer change at 5f3adf4 (2024-09-20)",
 "details": "Qwen2.5-1.5B: EOS changed from \"<|im_end|>\" to \"<|endoftext|>\"; anything fine-tuned or served against the old value stops at a different token (2024-09-20).\n\nRepository: https://huggingface.co/Qwen/Qwen2.5-1.5B. Revisions from 5f3adf4f8825bd43137c77c3d1db791c197b5bd3 onward carry this change; a pin at e5dfabbcffd9b0c7b31d89b82c5a6b72e663f32c or earlier does not.\n\nChanged keys:\n- tokenizer eos_token: <|im_end|> -> <|endoftext|> (tokenizer)\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/Qwen/Qwen2.5-1.5B",
     "events": [
      {
       "introduced": "5f3adf4f8825bd43137c77c3d1db791c197b5bd3"
      }
     ]
    }
   ],
   "database_specific": {
    "model": "Qwen/Qwen2.5-1.5B",
    "previous_revision": "e5dfabbcffd9b0c7b31d89b82c5a6b72e663f32c"
   }
  }
 ],
 "references": [
  {
   "type": "INTRODUCED",
   "url": "https://huggingface.co/Qwen/Qwen2.5-1.5B/commit/5f3adf4f8825bd43137c77c3d1db791c197b5bd3"
  },
  {
   "type": "PACKAGE",
   "url": "https://huggingface.co/Qwen/Qwen2.5-1.5B"
  },
  {
   "type": "WEB",
   "url": "https://www.neurarch.com/changes-feeds/models/Qwen/Qwen2.5-1.5B.html"
  }
 ],
 "database_specific": {
  "source": "neurarch model change tracker",
  "model": "Qwen/Qwen2.5-1.5B",
  "kind": "tokenizer",
  "classes": [
   "tokenizer"
  ],
  "changed_keys": [
   {
    "file": "tokenizer",
    "key": "eos_token",
    "before": "<|im_end|>",
    "after": "<|endoftext|>",
    "class": "tokenizer"
   }
  ],
  "impact": {
   "memory": false,
   "serving": true,
   "tokenizer": true,
   "licence": null
  },
  "breaking": true,
  "breaking_rule": "https://www.neurarch.com/changes-feeds/advisories/index.json#breaking_rule",
  "consequence": {
   "params": null,
   "weightsGbBf16": null,
   "trainPeakGb": null,
   "fingerprint": null,
   "context": null,
   "eos": {
    "before": "<|im_end|>",
    "after": "<|endoftext|>"
   },
   "bos": null
  },
  "commit_date": "2024-09-20T07:57:58.000Z",
  "detected_at": "2026-10-18T09:00:52.565Z",
  "detected_by": "backfill",
  "days_since_first_commit": 4,
  "license": "CC-BY-4.0"
 }
}