Documentation versions (currently viewingVaadin 23)
New Acceleration Kits: Kubernetes Kit and Azure Cloud Kit. Read the blog post.

Step 3 - Converting Legacy UIs

The UI object, which represents the <body> element in the page, is controlled by Flow when running the MPR, so anything extending UI should be converted. Actually, UI class shouldn’t be used for layout or navigation handling anymore. At the end of step 3, you shouldn’t have any UI class unless you have a real use case for it.

Depending on what’s used in the project, you have several conversion paths: