nextcloud-server/apps/user_ldap/appinfo/install.php

<?php
/**
 * @copyright Copyright (c) 2016, ownCloud, Inc.
 *
 * @author Arthur Schiwon <blizzz@arthur-schiwon.de>
 * @author Christopher Schäpers <kondou@ts.unde.re>
 * @author Roger Szabo <roger.szabo@web.de>
 *
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License, version 3,
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */
$state = OCP\Config::getSystemValue('ldapIgnoreNamingRules', 'doSet');
if($state === 'doSet') {
	OCP\Config::setSystemValue('ldapIgnoreNamingRules', false);
}

$helper = new \OCA\User_LDAP\Helper(\OC::$server->getConfig());
$helper->setLDAPProvider();