The Kunena team has announce the arrival of Kunena 6.2.6 [K 6.2.6] which is now available for download as a native Joomla extension for J! 4.4.x/5.0.x. This version addresses most of the issues that were discovered in K 6.1 / K 6.2 and issues discovered during the last development stages of K 6.2
Topics that are moved into this category are generally considered to be closed. Users may want to add additional information but these topics should not be resurrected in order to discuss new problems or unrelated matters.
Solved
Adding a new post does not show which category
I upgraded from Kunena 1.6 to the latest version. When I now click on "new topic" in the Kunena toolbar I dont get a dropdown box for the category. I dont know where the posts end up but people cannot post into the correct categories now.
I don't think anyone will be able to guess or imagine what the problem is without seeing either (or both) your website or your configuration report.
From the information you have given the most likely answer will be something wrong with your Joomla template it's certainly not a problem that as far as I know anyone else has.
Presumably you didn't have the same problem even you posted here?