I'd use the latest version of Seam and seam-gen to generate a new seam project, then migrate src and resource files. In the future you should be able to then update the seam-gen generate project when new versions of seam come out, as seam-gen has an update capability for automatic update conversion.
Thanks for the answer. This is exactly the way i travel when i can deploy on an app server (Jboss).
For older or newer applications not generated by seam-gen this is no solution.
The same holds for apps that must be deployed on tomcat without embedded ejb (using hibernate in the microcontainer). This kinds of applications are descendants of the seam application hibernate2.
I do have such a beast which will not behave well after i decided to upgrade. So the wish to have a migration guide.
I agree, an upgrade guide from release to release would be useful. However I doubt you'll get an upgrade guide that describes how to upgrade apps based on examples. I think your approach of taking the new hibernate2 example as a base and then patching in your code/config is the way to go here.
All that said, I wouldn't be surprised if any new update guide made references to seam-gen as it's a nice automated way to go. Later versions have a number of project types and deployment options. If your particular hibernate2 style project isn't yet able to be bootstrapped with seam-gen I'd submit an improvement JIRA for someone to take a look at supporting it in the future.