They still have that button, and you can go up by clicking on the parent folder name as well.
[Ctrl][Up] works in Vista onwards to move up a folder. It's worth knowing.
<Backspace> does this, since XP I think - ^↑ doesn't seem to work for me in Win 10.
Backspace is "back" not "up a folder level" as far as I am aware. This is consistent with web browsers - and indeed the conceptual meaning of "backspace" (go back 1)