After last update changes in Mouse class have been made. We cannot set position of cursor using old way. Right now we are able to ONLY get Mouse::pos(). How to set position?

You can't

Sorry but lets imagine situation when we want use cursor in center of screen as targeter... Right now we are forced to reproject and reimplement whole targeting system to one in which u use (?) 2d gui obejct which (?) is casted on 3d world or woot?

if you want center of the screen just use Vec2(0,0)
there's also Ms.clip and freeze to limit mouse movement