Upgrading

Composer constraints define the supported PHP and CakePHP versions. Use the version map when upgrading from older framework branches.

Use the view builder's serialize option rather than an _serialize view variable. Choose Feed.Rss or Feed.Atom explicitly, or use CakePHP's viewClasses() negotiation API. Old rss => Feed.Rss mapping examples are not the current controller API.

The unused RSS subDir property remains deprecated for compatibility. It does not select a template directory. Prefer template-free serialization and avoid depending on this property.

Native immutable dates are now accepted by RSS, and CDATA content containing ]]> remains valid XML. Atom title text constructs use the same HTML handling as other text constructs; XHTML is rejected consistently.

Check your feed's required fields, stable IDs, absolute links, MIME type, and enclosure metadata after updating. RSS and Atom serializers do not replace format validation or the application's access rules.

RSS GUID attributes now use the specification's isPermaLink spelling. The old @isPermalink input is accepted and normalized. Set @isPermaLink to 'false' for an opaque identifier that must not be expanded as a URL. RSS lastBuildDate is formatted like pubDate; date-only CakePHP objects avoid localized string parsing in both views. Null optional RSS values are omitted. Empty strings and false omit RSS date elements instead of producing an implicit current date. Null optional Atom constructs are also omitted.