It should be relatively easy to solve. All information tends to become obsolete, but you can usually predict at what pace. For example:
- How does this specific piece of software/hardware/technique work - is time-locked and will likely never become outdated;
- How do I do this in an operating system? - answers will likely change over several years (OSes don’t change as frequently as other things);
- How do I do this in a programming language? - answers will likely change over the months-years;
I think all such questions which only really vary by the “version” (the concept should be similar and understandable for non-technical topics) should be visibly connected to other versions of the same question and its answers, like the “Linked questions” sidebar widget on SE, so it would be easy to discover and navigate them.
Distinct communities should decide whether they want to keep “newer version answers/questions” on the same page or on separate pages if there is too much content and too much difference between the details of basically the same at its core question.