Change Proposal for ISSUE-140
Conformance to HTML should not have versions.
As previously resolved HTML is a language without versions. Introducing versions for conformance goes against this idea and will give the impression there is a difference between an "HTML5 conforming document" and an "HTML6 conforming document". The suggestion in the Change Proposal that applicable specifications could define their own terms will lead to a myriad of definitions related to HTML conformance and will not make the situation any clearer than simply using what is there today.
By not introducing versions in HTML conformance we keep it clear HTML does not use versions and we prevent the need to introduce lots of definitions around HTML conformance.