> For clean Markdown content of this page, append .md to this URL. For the complete documentation index, see https://buildwithfern.com/learn/llms.txt. ## 2.84.0 **`(feat):`** Object types with XML encoding metadata (e.g. TwiML) now implement `IXmlNode` with `ToXml()`/`ToXElement()`, static `FromXml(string)`/`FromXElement(XElement)` parsers, and fluent child builder methods (`response.Say("Hello", voice: "man").Dial(...)`). Unknown attributes and child elements are preserved in `AdditionalAttributes`/`AdditionalChildren` and re-emitted; `AddChild(XmlElement)` adds arbitrary elements. Parsing rejects malformed XML, mismatched root elements and DTDs. Types without XML metadata are unchanged.