Gareth, thank you.
That answer satisfied my question and will probably help others too.
I asked mainly out of curiosity and secondly because I read about the benefits of newer versions Bootstrap which do not necessarily bring any benefits to me.
In my practice I usually like to walk a little on the bleeding edge thus my question.
Also the looks of the new Boost theme are appealing and I am trying to understand where you will be taking Essential.
Sorry if I had you writing so much but thanks.