> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fiddler.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# IncompatibleClient

> Raised when the SDK version is incompatible with the Fiddler platform version.

This exception occurs during connection initialization when the evals SDK
version is not compatible with the connected Fiddler platform version. This
ensures that users are aware of version mismatches that could cause unexpected
behavior or missing functionality.

The message names both versions, for example "Fiddler Evals SDK version
(0.8.0) is not compatible with your Fiddler Platform version (26.20.0)."

## Example

```python theme={null}
from fiddler_evals import init
from fiddler_evals.exceptions import IncompatibleClient

try:
    init(url="https://your-instance.fiddler.ai", token="your-api-key")
except IncompatibleClient as e:
    print(e.message)  # upgrade the SDK or contact your administrator
```

Initialize the incompatible client exception.

## Parameters

**server\_version** `str` *required*

Version of the Fiddler server

**message** `str | None` (default: None)

Optional custom error message

## message

**Type:** `str`

**Value:** `'Fiddler Evals SDK version ({client_version}) is not compatible with your Fiddler Platform version ({server_version}).'`

Formatted message showing both client and server versions