Question about zypper updates on TW

I'm on Tumbleweed. Does zypper dup reload the current status of my repositories with newer packages, or do I have to run zypper ref first? Or is that what the man page means by "auto-refresh", and in that case, how do I configure that? The info I found online is conflicting. Wiki says zypper dup is enough, but it also says I get a notification about new packages, which I don't. I'm guessing that's only valid for Leap, but not sure about this either. Thanks.