# Sandbox.BlobData.Upgrade

```csharp
void Upgrade(ref Reader reader, int fromVersion)
```

Optional upgrade path for old data versions. Called if the data version is older than current Version.

### Parameters

- `ref reader` (`Reader`)
- `fromVersion` (`int`)

Declared in [Sandbox.BlobData](/api/Sandbox.BlobData).
Assembly: `Sandbox.Engine`.