1. Migrating is fun fun fun! Let's face it - migrating Plone site from old version to new one can be either painful or very painful experience. If you need to do it for one site only, you don't even get the reward of the fact that second time will be so much easier. Third time you'll start wondering what was the hard part in it. This post is intended to be description how we did plone migration from older version to new one with big, live and heavy traffic site . We're still middle of migrating rest of our sites and therefore I'm going to upgrade this description when I'm having more time. Also note that this is written with one go from memory and as doing the migration is quite complex thing to do including many tasks there might be some errors. I hope this gives some ideas to others struggling with the same topic and also raises some discussion why this is so complex to do when it shouldn't. I'm also happy to get comments how we could have done this be...