Thanks @andrayverysame.
as for the feather size, I couldn’t do that. Actually, I can’t change feather size anymore with other tools.
In 2.4.4, I would hover the mouse inside the shape and scroll the mouse weel (actually, I don’t have any mouse, what I do is scrolling the right side of the trackpad), and the feather size would change.
Now, it only changes the shape size, regardless where I hover the mouse (inside the shape, outside the shape inside the feather area)
At first, I was confused too, I was used to just use the scroll wheel.
It seems with the 2.6 the shortcut has changed, it’s now SHIFT + scroll (a tip should appear on the top part of the main window).