The feed above returns an XML document. I can successfully retrieve tag names like title,description and link using these codes 

```
    $xml = file_get_contents($feed_url);
    $xml = trim($xml);
    $xmlObject = new SimpleXmlElement($xml);   

    foreach ($xmlObject->channel->item as $item) {
      $title = strip_tags($item->title);
      $description = strip_tags($item->description);

    }

```

How can I get `<a10:updated>` ?

```
<rss xmlns:a10="http://www.w3.org/2005/Atom" version="2.0">
    <channel>
    <title>title/title>
    <link>link</link>
    <description>news</description>
    <item>
    <guid isPermaLink="true">link</guid>
    <link>link</link>
    <title>Tiele</title>
    <description>Descr</description>
    <enclosure url="image" type="image/jpeg"/>
    <a10:updated>2017-05-07T09:14:00+03:00</a10:updated>
    </item>
    </channel>
</rss>

```