There was a download of UISS 5.4.4 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The most popular versions among UISS users are 5.4, 5.3 and 5.2. UISS lies within Communication Tools, more precisely E-mail Tools.
We recommend checking the downloaded files with any free antivirus. The actual developer of the free software is ON6MU Guy Roels. The UISS installer is commonly called UISS.exe. The latest version of the program can be installed on PCs running Windows XP/Vista/7/8/10/11, 32-bit.
From the developer:
UISS is a program for packet radio communication with ISS (International Space Station), PCSat or compatible satellites. You can use it to connect and send pre-defined BBS commands or activate a beacon. UISS has a full BBS build in; it supports several external and remote commands. All commands are compatible with the commands used by GP (Graphic Packet) and uses the same operating as GP.
You may want to check out more software, such as Chilkat Mail ActiveX, 123 Bulk Email Direct Sender or Super Email Sender, which might be related to UISS.