Yathit Mobile App uses CRM subpanel layout metadata from get_module_layout REST API to render related panel.
Please verify that subpanel metadata in the app, as shown in the animated gif. In this example there are many panels to show related fields.
If the panels list metadata is not empty, but related panel is still empty, please [contact us](mailto: support@yathit.com).
If the panels list metadata is empty, contact your CRM administrator to check subpanel layout is configured to display some related data.