Upgrading my Nano from the UI worked flawlessly. Upgrading on my custom hardware box failed both from the UI and from the command line with 'upgrade-antman'.
Please see attached file (Wordfence wouldn't let me post the logfile)
Note: I am a licensed Essential user.
Also note: I had to upload my text file (.txt) named as .pdf to post this, so please rename to open and view.