Libre Office Writer new Interface

Libre office has been updated recently, adding a more modern and beautiful interface (icons, buttons, etc). This question NOT about the ribbon display - that I can deal with myself well.

I had installed in my machine Libre Office 5.5, with the following interface, which I think is ugly:
[![Ugly interface][1]][1]

I downloaded Libre Office 6, which promises a new interface, which I’ve been using in my other PC and I feel is more beautiful and intuitive:

[![Beautiful interface][2]][2]

I’ve trying installing on top (updating), removing and reinstalling. Deleting the folder, but nothing. The new Libre Office 6 comes with the same old ugly interface.

How to correct that and have a clean and beautiful Libre Office 6 interface installed?
[1]: https://i.stack.imgur.com/QuDU4.png
[2]: https://i.stack.imgur.com/h15vl.png

Open LO, go to Tools/Options/View and select icon set according to your wishes.