WordPress 2.9 will be released in just a few days. Fle4 is now tested to work correctly with 2.9. And the oldest version Fle4 supports is 2.7.
Fle4 also now has comment sorting, so KB comments can be sorted according to author, knowledge type, or date. This is still a bit hacky, and gets quite slow when you have like a hundred comments in the thread, but it’s there to play with.