The new Etude3 has been changed and the lower part of the casing has been made bigger to ensure more support for the thumb.
At this spot the surface has been made more course to "explain" where to put the thumb.
The Etude3 has an in height adjustable hook (for players with smaller hands)
The adjustment in height of the whole thumb rest has be done by pulling the casing down (not with the hook).
Some "clicks" will be heard. When you count these clicks , you will know that the thumb rest will be at the same height next time