php7.0 버전 업데이트 후 500 에러

PHP 7.0 버전 업데이트 이후에 아래와 같은 에러 메시지가 발생하며 500 에러가 발생하는데 어디 부분을 건드려야 해결할 수 있을까요?

 [Sun Sep 09 19:50:04.525721 2018] [:error] [pid 18168] [client 46.229.168.72:10296] PHP Fatal error: Uncaught Error: Call to undefined function xml_parser_create() in /home/surian/www/html/classes/xml/XmlParser.class.php:125\nStack trace:\n#0 /home/surian/www/html/classes/xml/XmlQueryParser.class.php(103): XmlParser->parse('<query id="getM...')\n#1 /home/surian/www/html/classes/xml/XmlQueryParser.class.php(63): XmlQueryParser->getXmlFileContent('/home/surian/ww...')\n#2 /home/surian/www/html/classes/xml/XmlQueryParser.class.php(90): XmlQueryParser->parse_xml_query('module.getModul...', '/home/surian/ww...', '/home/surian/ww...')\n#3 /home/surian/www/html/classes/db/DB.class.php(528): XmlQueryParser->parse('module.getModul...', '/home/surian/ww...', '/home/surian/ww...')\n#4 /home/surian/www/html/classes/db/DB.class.php(498): DB->checkQueryCacheFile('module.getModul...', '/home/surian/ww...')\n#5 /home/surian/www/html/common/legacy.php(144): DB->executeQuery('module.getModul...', Object(stdClass), NULL)\n#6 /home/surian/www/html/modules/module/module.model.php(1405): executeQuery('module.getModul...', Object(stdClass in /home/surian/www/html/classes/xml/XmlParser.class.php on line 125