My immediate take on this is:
version-number is only used once, and seems relevant in that context.
previous-versions refers to functionality provided by Windows to roll-back files; this tag is valid.
versions is already a synonym of version, so doesn't really exist.
version (and so versions), along with versioning, should probably all be synonyms to version-control. However, there's going to be a manual retagging job to be done here as I suspect many of the current questions are misusing them, but some will need saving.