2.22.0
(feat): Object types with XML encoding metadata (e.g. TwiML) now extend XmlSerializableType and
generate toXml()/toXmlElement(), fromXml()/fromXmlElement(), and fluent child builder
methods ($response->say('Hello', ['voice' => 'man'])). Attributes, text, namespaces, prefixes,
wrapped lists, separator-delimited lists and enums round-trip; unknown attributes and children
are preserved and re-emitted, and parsing rejects DTDs, malformed input and wrong root elements.
XML types add ext-dom/ext-libxml to composer.json and a Core\Xml runtime.