We have several CAB and prism 2 applications which we plan to migrate to Prism 4.
Has anyone any experiance with migration of CAB and/or Prism 2 applications to Prism 4?
I have just upgraded a large (30 module) Prism 2 application. It took about a day in total, but most of that time was spent changing namespaces and references. I followed the information Microsoft supplied when upgrading. Leaving the DI as Unity made the process much easier, it would have probably taken much longer if I had moved from Unity to MEF. I've yet to hit any "gotchas", will update this answer if/when I do.
It's worth noting the changes to commands otherwise you will come across InvalidCastException, T for DelegateCommand is not an object nor Nullable.