You can extend - or even override - the Roundcube configuration which is coming with this package in the file `conf/local.inc.php`. Do not edit the file `conf/config.inc.php` as future upgrades will overwrite it.
#### Multi-users support
* Integrate with YunoHost users and SSO - i.e logout button, YunoHost users search
#### Plugins
You can also install other plugins - which will not be removed with upgrades. To do so, you can use the official [Plugin Repository](https://plugins.roundcube.net/).
4. Enable it in the local configuration file `conf/local.inc.php` using your favorite text editor by adding:
```
<?php
$config['plugins'][] = 'html5_notifier';
```
Note that you should also check the plugin homepage for additional installation steps as needed.
##### Manual installation
You can also download the plugin and put it under the `plugins/` directory. In this case, do not forget to change ownerships of this folder to `roundcube`.