Create PDF 2.0 add-on is not accepted by Mozilla Firefox. The solution Adobe currently has posted to manually enable it in the Add-ons Management area of Firefox does not work (the "enable" button suggested in the solution is not present). The only solution Mozilla offers is to override the add-on signing in the configuration, but that would open up a hole in my security. Will Adobe have a Firefox compatible version of PDF creator released soon?
Adobe have now at least acknowledged the problem. My (outsider's) prediction is that there is a reasonable chance it will be included in the next quarterly update of Acrobat DC (subscription version). There is a lower but still fair chance it will be in Acrobat DC (purchased version). A negligible chance it will be for Acrobat XI. And none at all it will be in Acrobat X.