I see that Apache Tomcat 10 (alpha) is now available. The major feature there is support for Jakarta EE 9 where package names for APIs have changed from javax.* to jakarta.*. Jakarta EE 9 now has a milestone release available.
Can the current versions of Vaadin Flow (14 or 16) be made to work with the new Jakarta 9 and its name changes?
Vaadin does currently not support Jakarta EE 9 because of the package name changes. We’re watching to see how the situation develops to e.g. see whether application servers would include helpers to automatically also support parts that use the old package names.
In the mean time, you can try applying those changes manually using e.g. https://github.com/apache/tomcat-jakartaee-migration or https://github.com/eclipse/transformer/.