Inaccurate article on one point - they say that in 2014 it was proved the smallest number of moves to solve is 26... but in 2010 it was proven to be 20 moves actually. [1]. (And the article they linked to was from 2008 anyway and said that 25 moves was the max needed as of 2008 best knowledge)
The maximum number of face turns needed is 20, and the maximum number of quarter turns is 26.
Would have been nice if they mentioned the quarter-turn metric, and hadn't said "moves" then, which in speedcubing almost always refers to face turns. Especially when the article they linked to was regarding face turns as well.
They clearly refer to quarter-turn metric: “Finally, in 2014, it was shown that any valid cube can be optimally solved with at most 26 moves in the quarter-turn metric, or 20 moves in the half-turn metric [26, 25]. The quarter-turn metric treats 180 degree rotations as two moves, whereas the half-turn metric treats 180 degree rotations as one move. For the remainder of this paper we will be using the quarter-turn metric.”