I agree with the conclusions of Serg. I would howeverWe need to bring in a few practical issues involved in what you suggest:
- To decide if an answer not only is obsolete, but also gives no useful information whatsoever to solve the problem, is at least quite subjective, probably undoable. I remember occasions where answers were strictly taken obsolete, but gave me nevertheless useful information to look in the right direction.
- Apart from that, also because of that, making decisions on what answers are obsolete or not, would be a very time consuming task. Who would you like to do that? How would you suggest to create consensus on that?
Already mentioned, but nothing keeps you from adding an answer, starting with for 16.04:.
Removing possibly obsolete answers would make things unnecessarily complicated, make us lose valuable content, is a burden to the review- capacity and would make no sense to the voting system.