IMHO the answer is - it depends. First, I would do as Gerry said and migrate your current PFC/E and try that out. Make a backup before and after. If it works, decide if you need any of the new functionality. If you are using the version 5 PFC, you don't have any of the unicode or platform specific code. It mostly depends on how long you think the application(s) will be around. For maintainability, it's always best to be on the current version, and again, you may need to add some unicode functionality or use the platform services going forward.
If you know what PFC objects were changed, you could try doing this:
1) Make backups!
2) Download the new PFC/E and overlay the PFE with your changed ones. Depending how many changes there were, you might want to go object by object instead of full PBLs.
3) See if the changed PFC in your old libraries can be implemented in PFE objects instead, and do that.
4) Regen, optimize and test.
Evaluate the PFC/E changes. If they were made in version 5, there's a pretty good chance whatever was being "enhanced" could be taken care of in a newer version. You could even try just using the new PFC/E and seeing what breaks in testing, and evaluate from there.
Good luck,
Kevin
