Yii HTML version 4 was released. In this version:

• Allow passing int, float and null as tag content
• Throw LogicException in Tag::id() when id is empty string
• Remove tag attributes sorting
• Make all CheckboxItem and RadioItem properties required
• Rename $options parameter to $attributes in Html::addCssClass(), Html::removeCssClass(), Html::addCssStyle() and Html::removeCssStyle() methods

See upgrading instructions with notes about upgrading package in your application to this major version.