Testopia 2.5 will work with Bugzilla 4.2.1 pretty decently
You probably noticed that there has been no activity related to the development of Testopia, a Bugzilla extension, for more than a year. The reason is that its maintainer, who was the single contributor to this project, had a new job and has no time to work on it anymore. Consequently, the latest version of this extension, Testopia 2.4, which was released in October 2010 (!), only works with Bugzilla 3.6, but not 4.x.
You will be happy to hear that with the help of some new contributors wanting to make Testopia work with Bugzilla 4.2, I committed several patches to the bzr repository which make it work pretty decently with Bugzilla 4.2.1 (probably also with Bugzilla 4.0.x, but I didn’t test). There is no official release yet (it should be named Testopia 2.5), but you can download updated files using bzr. Make sure to revert changes made to the core code of Bugzilla first before applying the new code.
To make things clear: I’m not the new maintainer of this extension, and I have no plan to take this role. I’m busy enough with my roles as assistant project lead + reviewer + QA lead + bug triager + developer for the Bugzilla project. I simply decided to help the new contributors who jumped in these last few days and used my commit access to the Testopia repository to commit some patches. The Testopia maintainer is still alive, and emailed me this morning. So he is still the one who will take the decision to release 2.5 when it’s ready. 
Update: Starting with Bugzilla 4.2.1, you no longer need to patch the source code of Bugzilla to make it work with Testopia 2.5! If you are upgrading from Testopia 2.4 or older, make sure to revert the changes made to the source code first.
Hello, my name is Igor Podobnik from Slovenia and i’m a tester in my company. We’re also using Testopia and are extremely grateful for your contribution. We’ve just upgraded our Bugzilla and are glad that we could keep Testopia with it.
However I would like to ask you if you know of a way to export the test cases from the old version and import it into a new one. I have tried but it seems that the old XML export does not match the new XML import so I can’t import it. Do you have any suggestions as to what to do?
Thak you again!
i have installed testopia 2.5 . it is working fine. but my doubt is how to import existing test plan into testopia. in my company we are using test plan with diferent fields. can any one please give your solution to inporting the test plan