yeah, or you would have:

```
struct Old { A, B }
struct New { Old, C }
impl Into<New> for Old { ... }

let settings = if let Ok(settings) = from_bytes::<New>(...) {
    settings
} else {
    if let Ok(s) = from_bytes::<Old>(...) {
        s.into()
    } else {
        Settings::default()
    }
};
```