The company I work for is using Vaadin 7.7.30. I’ve been given the task to calculate how much time it would take to migrate this version to Vaadin 14, if possible. I would like to ask for assistance in determining the exact order in which the components should be replaced. Is it even worth replacing a non-DOM-based, heavyweight backend and frontend app (developed for over 10 years) with a DOM-based Vaadin or should we consider switching to Angular instead, as the new Vaadin is also DOM-based? Do we need to upgrade the Java version for the Vaadin version upgrade?
If you are already on 7.7.30 means you have Vaadin Prime or above support in your contract. You should really get in contact with them to get proper answers to your questions. It’s close to impossible without code insights to tell you “you need 5 days to migrate”
Wondering why you’re looking at Vaadin 14 instead of the latest
Vaadin also offers a Upgrade Assessment service, which is designed exactly to answer those kinds of questions
We doesn’t have Vaadin Prime, that is why asked here. But thanks the answers anyway 
How are you running 7.7.30 then? 