I did the upgrade and ran into some problems that have made my tikiwiki site useless:
1) After upgrade, the search feature doesn't work. With over a hundred pages, my users can't find anything anymore. Terms like "billing" which used to bring up articles on how to do billing now return "no pages found." However, articles added after the upgrade appear to be found. Do I have to re-index the system?
2) The home page wouldn't come up. We were using an edited version of the 4.3 default page which included an RSS feed from reuters. The feed failed to work after upgrade causing the home page to appear blank and locking users out of the system. I fixed this by logging in a Admin, and removing the RSS feed.
I am hoping someone knows what's going on here!