There were a few hangups with the latest RC.
First, I wanted to get the test suite finished. My goal was to have a fully automated set of tests that could be run against a sample database to demonstrate all the features of Testopia. I have had the help of a couple of students from Neumont University that have done a great job getting this started. The tests are in the testopia/t folder. What is there is a good start, but I plan to refactor it multiple times in the near future to get it up to snuff.
Second was to get the XMLRPC API fully developed. As of today it is functioning very well. This version introduces batch mode processing as well as a host of improvements. There are a number of changes that are incompatible with the old version unfortunately. The differences can all be viewed in the CHANGELOG and the updated docs can be found at http://landfill.bugzilla.org/testopia2/docs/html/api/index.html
Finally, I really needed to squash that JSON version incompatibility bug. I think it is finally working with the new version of JSON. The latest, 2.10, is required. This means you will need to update JSON before updating Testopia. You might also want to install JSON::XS which will speed JSON up considerably.
If I don't see any serious bug reports in the next week or so, this will likely be the final release candidate.