Sets a default retention policy

functions.php

<?php
function default_gravity_forms_retention_policy( $form, $is_new ) {
  if ( $is_new ) {
    $form['personalData']['preventIP'] = true;
    $form['personalData']['retention'] = [
      'policy'                => 'delete',
      'retain_entries_days'   => 45
    ];
    GFAPI::update_form( $form );
  }
}
add_action( 'gform_after_save_form', 'default_gravity_forms_retention_policy', 10, 2 );