I looked at http://elm-lang.org/ and the "Install" link (to make sure there was no comment about not using it in production). There is no mention of the version number anywhere. There are, however, testimonials from (what sound like) real companies using it in production.

I think the problem there is that far too many projects live in that world for years and years and years despite being obviously used in production.

At this point if a project has been around for a long time and has version numbers like that I just assume it’s not real semantic versioning.