We knew this was coming… and the announcement is finally here. Fortunately we have over two full years to learn Experience Builder (or Dashboards or Instant Apps) and migrate our apps. 🙂
Existing apps will continue to work after the retirement date, but no new apps can be made. Additionally there may be technical or security issues with WAB apps moving forward after retirement date.
For complete details and plenty of great resources please see this blog post from Esri: https://www.esri.com/arcgis-blog/products/web-appbuilder/announcements/arcgis-web-appbuilder-roadmap-for-retirement/
There is a good matrix of features (and when they are coming to experience builder).
https://community.esri.com/t5/arcgis-experience-builder-documents/functionality-matrix-for-web-appbuilder-and/ta-p/1113766?lightbox-message-images-1113766=63737i93122EB1B6232FC9
Ditto!
**sad, crying emoji**