When we updated the Twitter API to v1.1, we retired the XML response format from our endpoints, but we continued to support it on our oEmbed implementation because it was a public standard. Since then use of the XML format has significantly declined, so it no longer makes sense for us to maintain that support. After May 1, 2016, we will be removing the XML response format from the single Tweet oEmbed endpoint. Going forward, JSON will be the response format for all Twitter APIs.
A request for an XML-formatted Tweet oEmbed response may exist in your code as:
Update any affected code to request and decode a JSON response instead: