The following workaround can be used to run the refresh command in PHP 7.2.$dn= 'cn=user,dc=test,dc=org';$ttl = 3600;$data = '';$data .= '80' . sprintf("%'.02x", strlen($dn)) . bin2hex($dn);$data .= '81' . sprintf("%'.02x", 4) . sprintf("%'.08x", $ttl);$data = hex2bin('30' . sprintf("%'.02x", strlen($data)/2) . $data);$success = ldap_exop($ldapHandle, LDAP_EXOP_REFRESH, $data);