This is how I handle product versions within questions, mainly at the GIS Stack Exchange, with respect to each of the three question components:
Normally, I exclude version numbers from titles because most solutions apply to more than one version mostly for the important reason you identified:
it attracts attention way after version N is deprecated, including
answers for more recent versions
but also because it enables titles to be more concise.
The only time I think a version number in a title may be appropriate is when the issue has been shown to be present in that version alone i.e. it is not in earlier versions and is not (expected) in later versions.
In the question body, version information is critical. The more information that appears about the version(s) in which a problem has been seen, the better it is for anyone trying to understand the Q&A i.e. potential answerers and later readers alike.
I think it is important to use version tags whenever there are large numbers of questions about a product on a site, especially if it is a rapidly evolving product. For smaller products the question volume will often not warrant them. I try not to apply too much or too little granularity. In the product I know best I use version tags for dot releases but not for anything more minor like service packs, etc.
I use version tags to find problems by their vintage. If someone is reporting a problem that I cannot reproduce in the latest version, I use these tags to step back a version at a time, or jump to the version where I may have a vague recollection of having seen it to sift more quickly through Q&As to find potential duplicates.