As indicated in its home page (http://spamfu.net/):
SpamFu Proxy: is intended to be a replacement for saproxypro, as it has been announced that there were no further plans to develop or sell saproxypro.
SpamFu Proxy is intended to fill the void, and was built to be the functional equivalent of saproxypro.
SpamFu Proxy uses the same set of open-source scripts (pop3proxy.pl and sa-learn.pl), the same conversion tools (dbxconv.exe and readpst.exe), and the same libraries (SpamAssassin, DCC and Razor) that saproxypro used.
Additionally, we (SpamFu people) are committed, as much as possible (?, by wiki page editor), to keeping the underlying source code open and easily accessible. In general this will include everything but the GUI itself.
As per author email in as per http://sourceforge.net/mailarchive/forum.php?forum=spamassassin-saproxy:
- human author of saproxypro
- It is free, and always will be; Everything except the GUI itself is open source.
- It's got a nice installer that will migrate your SAPP settings if you have them.
- It currently utilizes a slightly modified SpamAssassin 3.02
- Please download it and beat on it and give feedback.
- a wiki will be set up in the next few weeks to make communications easier.
- Also, none of the work is checked back in to SA"s SVN repository. If anyone wants to take on that chore, feel free.
Forward looking to a be able to provide a sourceforge or equivalent project page ... (comment of the wiki page editor)
Seem to be positive as per http://sourceforge.net/mailarchive/forum.php?forum=spamassassin-saproxy