Windows 7, Vista, or XP (depending on version).
The official Cyberduck Changelog contains links to every historical version of the software. To find a version compatible with your 32-bit system: Navigate to the Official Changelog. Scroll down to or earlier. cyberduck 32 bit download
When choosing an older 32-bit version, ensure your system meets the corresponding requirements: Windows 7, Vista, or XP (depending on version)