This document will help you upgrade from antd `4.x` version to antd `5.x` version. If you are using `3.x` or older version, please refer to the previous [upgrade document](https://4x.ant.design/docs/react/migration-v4) to 4.x.
1. Please upgrade to the latest version of 4.x first, and remove / modify related APIs according to the console warning message.
## Incompatible changes in v5
### Design specification
- Basic rounded corner adjustment, changed from `2px` to four layers of radius, which are `2px``4px``6px` and `8px`. For example, radius of default Button is modified from `2px` to `6px`.
- Global shadow optimization, adjusted from three layers of shadows to two layers, which are used in common components (Card .e.g) and popup components (Dropdown .e.g).
- Overall reduction in wireframe usage.
### Technology adjustment
- Remove less, adopt CSS-in-JS, for better support of dynamic themes. The bottom layer uses [@ant-design/cssinjs](https://github.com/ant-design/cssinjs) as a solution.
- All less files are removed, and less variables are no longer exported.
- Css files are no longer included in package. Since CSS-in-JS supports importing on demand, the original `antd/dist/antd.css` has also been abandoned. If you need to reset some basic styles, please import `antd/dist/reset.css`.
- Remove css variables and dynamic theme built on top of them.
-`babel-plugin-import` is no longer supported. CSS-in-JS itself has the ability to import on demand, and plugin support is no longer required. Umi users can remove related configurations.
-`getPopupContainer`: All `getPopupContainer` are guaranteed to return a unique div. This method will be called repeatedly under React 18 concurrent mode.
- Static methods are no longer allowed to dynamically set `prefixCls``maxCount``top``bottom``getContainer` in `open`, Notification static methods will now have only one instance. If you need a different configuration, use `useNotification`.
-`close` was renamed to `destroy` to be consistent with message.
If you encounter problems during the upgrade, please go to [GitHub issues](https://new-issue.ant.design/) for feedback. We will respond and improve this document as soon as possible.