# not_a_base_line

> Only a base line (in no package, and not itself an upgrade) can be replaced.

**Not a base line** · HTTP 422

## What it means

Only a base line (in no package, and not itself an upgrade) can be replaced.

## What to do

Replace the base line instead.

## Example

```json
{
  "type": "https://api.bymundi.com/problems/not_a_base_line",
  "title": "Not a base line",
  "status": 422,
  "detail": "Only a base line (in no package, and not itself an upgrade) can be replaced.",
  "code": "not_a_base_line",
  "requestId": "req_…"
}
```

How to read any error: [Errors guide](https://api.bymundi.com/docs/guides/errors.md).