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## 2.40.0

**`(feat):`** Add support for client-side default parameter values via `use-default-request-parameter-values` flag.
When enabled, query and header parameters with defaults become Optional types and defaults are automatically
applied when not provided. Example:

```yaml
customConfig:
  use-default-request-parameter-values: true
```

Generated code:

```java
// Parameters with defaults become Optional
private final Optional<Integer> perPage;  // Has default: 50

// Defaults are applied automatically
QueryStringMapper.addQueryParameter(httpUrl, "per_page", request.getPerPage().orElse(50), false);
```