Just as I predicted, the scammers behind WinZix has changed everything around in the ZIX format. They even altered the header, which I failed to predict.
Otherwise, it's just what I feared. The manifest is encrypted, if there is one at all. Everything about the old format is now obsolete.
Not being a natural hacker/cracker (I much prefer writing my own software), I'm not sure I can decrypt this mess. Over the next few weeks, I'll dedicate what time I can spare to trying out a few common degarbling/decrypting methods and see if I can get anything useful out of it. In the meantime, all I can do is to update UnZixWin to recognize the new header information and show a 'sorry - can't do it' message. Bummer! Look for a version 0.0.8, coming very shortly.
Also, I'll update the ZIX docs to include whatever information I can dig out of the new ZIX archives.