Okay.. the time has come for us to migrate from Plone 2.1 to Plone 2.5 on the Faculty web site. The word is that this migration should be much easier than the migration was from 2.0 to 2.1.. so here is a little log of my experience:

• Given that requirements for Plone 2.5 include Zope 2.8.7+ or 2.9.4+ and we are running 2.8.5, I put in a request to the network support guys to upgrade Zope. They upgraded to 2.10.1 (which would seem to meet the requirement of 2.9.4+) and gave me the reigns.
• Tried migrating the dataface site using the portal_migration tool. The migration appeared to be successful, so I proceeded to do a version migration on the portal_atct tool. That migration also appeared to be successful. Wow! Was that ever easy! But wait a minute …..
• When I tried to visit some of the pages of the migrated dataface site, I received “404 resource not found” errors. Something went wrong, but what?
• I then took a step back and tried something simpler: adding an empty plone site using the ZMI on a default Plone 2.5 install. The installation failed with errors.
• I began to suspect that Plone 2.5 was not compatible with Zope 2.10, so I did some googling and found out that indeed it does not work. The requirement of 2.9.4+ actually means 2.9.x where x >= 4 – and NOT x where x > 2.9.4.
• Then I got another bright idea: The requirements listed on the plone site for Plone 2.5 were identical to the requirements for Plone 2.1.4. We were running Plone 2.1.2 fine on our Zope 2.8.5 box so I thought maybe the 2.8.7+ requirement might be lax on the last digit, and that 2.8.5 would work. WRONG! It didn’t work.
• Sent in a message to the network guys asking for a different Zope install (we’ll eventually have to upgrade to Zope 2.10 for Plone 3, but that won’t be for a while.
• Now with my newly installed Zope 2.9.6 instance I was ready to go to town.
• I ran a migration on the dataface site using the portal_migrations and portal_atct tools, and tested the site out. The migrations went smoothly (took about 20 minutes, but everything works tickity boo).
• The Faculty site is another story. We are using CAS authentication on the site so that users can use the SFU single-sign on features and we don’t have to handle passwords. Apparently Plone 2.5 using PAS (Pluggable Authentication Service) which is quite different than the old system and doesn’t support migration of CAS User Folders. Hence the migration in portal_migrations failed.
• Googling on the internet led me to a number of pages describing this issue. Apparently the current workaround for this is to delete the CAS User Folder and do the migration, then install CAS4PAS – an alternative CAS product that works with Plone 2.5. The problem is then I think we may lose all of the user roles, groups and permissions. 🙁
• To be continued ….