I've seen a lot of Q&A on meta.SO which are hopelessly outdated. If they are precious (EG, historical significance), how about a big note on top of them outdated! here's something newer that might be related, or something along those lines?
Generally I favor deletion in this case, unless there is something exceptionally valuable to capture in the discussion.
Although, I suspect at least one user quit the network over my propensity for deleting what I believe to be outdated information on meta, so -- opinions vary.
Either way, PLEASE flag such things for mod attention. I will look at them!