I saw the follow:
The following error just broke Matomo (v4.9.1):
Call to undefined function Piwik\Plugins\RssWidget\simplexml_load_string()
in /srv/matomo/plugins/RssWidget/RssRenderer.php line 62
when visiting /index.php?date=yesterday&module=RssWidget&action=rssPiwik&disableLink=0&widget=1&idSite=8590&period=day
Going to /index.php?date=yesterday&module=RssWidget&action=rssPiwik&disableLink=0&widget=1&idSite=8590&period=day is not expected to throw an error.
An error is thrown when going to /index.php?date=yesterday&module=RssWidget&action=rssPiwik&disableLink=0&widget=1&idSite=8590&period=day.
Maybe it should be like:
$rss = @\simplexml_load_string($content);
if ($rss === false) {
throw new \Exception("Failed to parse XML.");
}
?