Just to give some feedback, we finished PRADO4 migration of our project by now. We include PRADO via composer - since there is no stable v4 version yet, we use the master branch in production ... no "don't do" bashing please :smile:. The project passed our tests and QA and is already rolled out to some customers. The whole process took nearly 3 months, major problem was missing namespaces on templates and in class files together with including 3rd party libraries (and their dependencies). Minor problems were overridden or extended PRADO components with changed logic and asset/js management. If anyone has specific problems during migration, feel free to ask - maybe I can be of help.