Simple question: is it possible to upgrade Vaadin 24 to Spring Boot 4 before making the upgrade to Vaadin 25? I have tried that and got a java.lang.ClassNotFoundException: org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration
Kind regards,
Ulrich
No, it is not possible. Spring Boot 4 requires some changes in Vaadin, that have been made only in Vaadin 25. To be precise, Vaadin 25 release was done few weeks after Spring Boot 4 exactly for this reason.
Ok thanks a lot for the information.
It’s a bit unfortunate though, because I was hoping upgrading to Vaadin 25 would not be yet another Big Bang migration, but could be done gradually.
You can do most of the needed changes related to Spring Boot if you update to the latest 3.x version and make sure you’re not using any deprecated APIs.
Yep thanks, I’ve already done that. But there are breaking changes in Spring Boot 4, which may not relate to Vaadin, but are an issue for applications. On top of that Vaadin drops support for some of its own APIs like the old Upload API, if I’m not mistaken. So it’s a lot on the plate already…
The APIs in e.g. Upload that were deprecated when we added UploadHandler remain as deprecated also in Vaadin 25 so no need to handle that specific case before upgrading. There are also various other workarounds e.g. a feature flag to keep the old CSS loading behavior documented in the upgrade guide at How to upgrade Vaadin applications.