You're misreading the article, I think. They didn't release a new version under the GPL. They didn't retroactively undo licensing for older versions. It is not

You're misreading the article, I think. They didn't release a new version under the GPL. They didn't retroactively undo licensing for older versions. It is not at all clear that you can snap your fingers and renegotiate an existing license arbitrarily like that. You need to do it in advance of the agreement.