- Questions about pre-releases, especially testing/debugging, that have since been released.
- Questions specifically about releases that are no longer supported (now Luna)
I adamantly oppose any discrimination against Luna. Although it isn't supported officially anymore, it doesn't cease to be the second-latest stable version of the OS, many people still use it, and this kind of platform exists precisely to allow peer-to-peer support alongside (or in this case, in the absence of) official support.
As for obsolete questions, as long as they truly won't apply to anyone else (e.g. someone who happens to still use a previous release, someone who hasn't updated their system, etc.), I could (in principle) agree with a proposal to have them hidden, deleted or closed.
However, I'd point out that we don't have a space limit, and if the issue indeed doesn't occur to anyone else, then as long as the question is properly titled, it simply won't be searched for or found anymore, and would remain part of the archives, stats, and cultural memory of the site (i.e. as a potential example of how questions should be answered, or what questions shouldn't be asked here, and so on). In other words, they wouldn't be causing any harm, so why not just let them drift towards obscurity if that's what they're destined to?