Change record status: 
Project: 
Introduced in branch: 
11.2.x
Introduced in version: 
11.2.0
Description: 

The use of #type => 'fieldgroup' in form elements to group form elements together is no more used. Use the 'fieldgroup' as a class in #attributes of form element and #type => 'fieldset'.
Also need to add the core/drupal.fieldgroup library where #type fieldgroup was used in the form.

Before:

    $form['site_information'] = [
      '#type' => 'fieldgroup',
      '#title' => $this->t('Site information'),
      '#access' => empty($install_state['config_install_path']),
    ];

After:

    $form['#attached']['library'][] = 'core/drupal.fieldgroup';

    $form['site_information'] = [
      '#type' => 'fieldset',
      '#attributes' => ['class' => ['fieldgroup']],
      '#title' => $this->t('Site information'),
      '#access' => empty($install_state['config_install_path']),
    ];
Impacts: 
Module developers