For v4 and below, you’d need to add in:
'field_groups' => array(ACF_POST_NUMBER),
to the ‘acf_form’ array, making sure to check what your ACF post number is and replacing ACF_POST_NUMBER with it.
Eg.
<?php acf_form(array(
'field_groups' => array(5),
'post_id' => 'new',
'submit_value' => 'Neuen Datensatz erstellen'
)); ?>
