YUI 3.5.0 Preview Release 4 是 YUI 3.5.0 版本的最后一个测试版本，正式版将于四月中旬发布。
- The old (3.4.1) Uploader and DataTable modules have been deprecated in lieu of new replacements and are now available as uploader-deprecated and datatable-*-deprecated, respectively.
- Button underwent a significant refactoring. Please take a moment to check out the new API and file any issues in our bug tracking system.
- WidgetButtons, which adds support for buttons in a Panel has been significantly improved.
- A new event submodule, event-contextmenu has been introduced.
- Calendar has been made keyboard-navigable and accessible, and calendar navigation now supports disabled button states.
- Uploader's queue management has been refined, and UploaderFlash now supports keyboard navigation.
- App.Transitions has added cross-fade and slide transitions to Y.Apps.
- Y.Handlebars has been fully and thoroughly documented.