Google Apps Script - Xml API has been suspended

I have a Google Apps Script script but I got the following error:

  

The Xml API has been suspended.    The API has been flagged as disapproved, which means that the resource should be avoided and can be removed later. Consider using another   solution.

Below the code snippet:

var xmldocument = Xml.parse(xmlContent, true);
var items = xmldocument.rss.channel.getElements("item");

for (var index = 0; index < items.length; index++) {        
    var jiraKey  = items[index].getElement("key").getText();

I changed the parse to use var xmldocument = XmlService.parse(xmlContent); but I got the following error:

  

TypeError: Can not read property "channel" from undefined. (line 185, file "Jira Validation"

Does anyone know the best solution to this problem?

Thank you.