[Solved] Since using RegistrationMagic the Biographical Info of new WP-Users is not transfered into "About me" of the wpForo-Profile  

@bvsc,

Please note, that there are hundreds of plugins which interacts with user fields. All these plugins may save those data in X fields of Y tables. This is something that cannot be predicted and integrated.

wpForo doesn't have to support all those hundreds of plugins. The RegistrationMagic is one of those hundred plugins.

The solution is asking for integration. We may do that or not, and we'll be right in both cases. In the same way you should ask RegistrationMagic developers to integrate their fields with wpForo. And they may do this or not, and again, they'll be right in both cases. The developers of plugins don't have to integrate any plugin with any other plugin. So if one plugin is not integrated with second plugin it's not a bug. It's normal.

I can provide you a small code to try to integrate the "Biographical info" field. But I can't support other custom fields. To make the "Biographical info" field working with wpForo you should insert this PHP code in your current active theme functions.php file:

function registrationmagic_wpforo_integration( $user ){
   if( !empty($user) ){
        $user['about'] = get_user_meta( $user['ID'], 'description', true );
   }
   return $user;
}
add_filter('wpforo_profile_header_obj', 'registrationmagic_wpforo_integration', 10, 1);

How to Easily Add Custom Code in WordPress (without Breaking Your Site).

This code will integrate RegistrationMagic "Biographical info" field in forum user My Profile > Account fields. If you want to display the "Biographical info" field information on My Profile > Profile Home page you should  add a small code in wpForo core file. Use some FTP client or your Hosting cPanle > File Manage, open this file: wp-content/plugins/wpforo/wpf-includes/functions-template.php

Find this function:

function wpforo_profile_page_field_values( $fields ){
   if( isset(WPF()->current_object['user']) && !empty(WPF()->current_object['user']) ){
      $user = WPF()->current_object['user'];
      WPF()->data['value'] = $user;
   }
}

Change it to this:

function wpforo_profile_page_field_values( $fields ){
   if( isset(WPF()->current_object['user']) && !empty(WPF()->current_object['user']) ){
      $user = WPF()->current_object['user'];
        $user = apply_filters('wpforo_profile_header_obj', $user);
      WPF()->data['value'] = $user;
   }
}

This change is already added in wpForo core, so you'll be able to update it in the future without any issue.