I say let's follow the approach used by Stack Overflow, where generally questions don't have version-specific tags unless the question is specific to a particular version. For example, there are version-specific Python tags "python-3.3" etc, but most questions should use the generic "python" tag.
However in the case of Inform, there are effectively entirely separate languages Inform 6 and Inform 7, so we should probably use separate inform6 and inform7 tags. (I've now retagged the Inform 7 questions).