• 新增 Upload 的 before-remove 钩子方法，#8788（by @firesh）
• 修复 FormItem 的 error 属性初始值无效的问题，#8840
• 通过指令调用的 Loading 现在支持以 element-loading-custom-class 属性的方式设置自定义类名，#8826（by @earlymeme）
• 修复 CarouselItem 为异步获取时被隐藏的问题，#8921
• 新增 Tree 的 renderAfterExpand 属性，#8972

• Added before-remove hook function for Upload, #8788 (by @firesh)
• Fixed initial value of error not working for FormItem, #8840
• Now Loading directive supports custom class name by assigning element-loading-custom-class attribute, #8826 (by @earlymeme)
• Fixed CarouselItem becoming invisible when data is asynchronously updated, #8921
• Added renderAfterExpand attribute for Tree, #8972