Weasel 2.37 had been released:
URL: http://www.pmoylan.org/pages/os2/Weasel.html
"Weasel: a POP3 and SMTP daemon for OS/2. Includes controls on who may send relay mail, and includes a way of blocking mail from specified hosts. This software was "optional shareware". What this means was that you decided whether you wanted to register as a paid owner of the software. The author will continue to provide support, for at least the short-term future.

Many thanks to Peter Moylan, the author, who on 17/09/2014, released as GPL License the source code of one of the most used mail server on OS/2.
Source:eCSoft/2