From the article: "an acceptable compromise has been found, and the text-only option will remain. But, once a year, those subscribers will get a message asking

From the article: "an acceptable compromise has been found, and the text-only option will remain. But, once a year, those subscribers will get a message asking them to click on a link to confirm their continued interest in remaining on the list. That should allow Mozilla to prune its inactive readers" So that's exactly what Mozilla actually ended up doing.