---
title: V4.2.1
description: Upgrade guide from older versions to FastGPT V4.2.1
---

For self-hosted deployments with a custom configuration file, you need to update the `VectorModels` field. Add `defaultToken` and `maxToken` — these correspond to the default token count for direct chunking and the maximum token limit supported by the model (generally recommended not to exceed 3000).

```json
"VectorModels": [
    {
      "model": "text-embedding-ada-002",
      "name": "Embedding-2",
      "price": 0,
      "defaultToken": 500,
      "maxToken": 3000
    }
]
```

The rationale behind this change is that there's no need to offer multiple choices — just pick the most suitable model for the task.