As a relative newcomer, having the forums by version seems like a very bad idea. A lot of the material in older versions is still applicable as the new versions come out. Therefore for a novice one would have to do the same search in each versions forum, in order to answer a query, wasting a lot of time. I like the new format.
If people listed their version, as is required on some sites, then a person only interested in a particular version could include that in the search -- with the caveat that if the question was answered in an earlier version, they would not get an answer.