> For the complete documentation index, see [llms.txt](https://docs.socialstream.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.socialstream.dev/features/auth-existing-unlinked-users.md).

# Auth Existing Unlinked Users

This feature isn't new to Socialstream, but is a renamed version of the now deprecated ["Login on Registration"](/features/login-on-registration.md) feature.  <mark style="background-color:orange;">Please update your application to use this feature instead</mark>

Enable this feature if you wish to allow users to link a new provider to an existing user in your application without them being authenticated.

{% hint style="warning" %}
This feature can allow compromised social accounts unsolicited access to your users accounts.
{% endhint %}

To enable this feature, add the following to the `features` array of your `socialstream` config file:

```php
Features::authExistingUnlinkedUsers()
```