I also just got S-off tonight myself on Hboot 1.57.
It did not come without serious headache though. I had to sent my other Htc One back to Att due to the purple camera crap. They sent me a new one since my warranty was still good for another week. I got it rooted and unlocked but could not get s-off. I posted in another thread my continuous dots I was getting.
That was last weekend, so I read more today and thought I'll just download a cm nightly rom and cwm which seems like a combo that people say is working for them. So I did just that, well for some reasons, when I would run firewater, it was not happy with how I was rooted??? I finally gave up after several roms ahrd 53.0, cm nightly's, twrp, cwm, and said screw it, I'm gonna wipe this mother completely, so I wiped data, and then had to adb sideload the ahrd 53.0 to it. Once that was loaded, then I ran firewater again, this time it went further than it had ever done, it got to the second bottle and chugging, and then just hung there. So I rebooted adb, and tried it again, the next time it took 3 bottles but came back with S-off.
So the only thing I did differently that did work was I had done a wipe but not a full 100 percent wipe then sideload a rom. Hope that helps somebody who gets in a pinch.