Hello Jianxia.
Thank you for your reply.
There are two questions that I think developers will need some clarification.
1. Are there any plans to enable developers to build 2D widgets in Web Appbuilder using JS API 4.x?
2. When the Experience Builder is ready, after all the out-of-the-box widgets migrated to this platform, will ESRI continue to update the web Appbuilder with new versions (widgets and themes)?
Thank you.