Admins can now map domains to specific profiles.
To do this add this array to your advanced config:
'custom_domains' => [
['domain' => 'example.com', 'name' => 'example_user',],
['domain' => 'example.example.com', 'id' => '1',],
// more entries as needed
],
For each entry, a domain and user name or id has to be defined.