The installer, x2goclient-18.104.22.168-2016.09.20-setup.exe , is available under this folder:
X2Go Client is currently only released as a 32-bit x86 build. Both 32-bit x86 and 64-bit x86 versions of Windows are supported via this build.
These versions of Windows without the latest (specified) service pack / major update may be compatible, but are rarely (if ever) tested. They are not officially supported.
Corresponding server versions of Windows are also supported, but receive minimal testing:
Any incompatibility or bug with a specific version of Windows should be reported via our bug-tracker.
Deprecated versions of Windows are going to become incompatible in the coming months. Cygwin has already dropped support for them, and upgrading all the Cygwin components is planned for the coming months.
See this page:
bug 611 The server cannot be added to the known_hosts file (and thus you cannot connect to the server) when both of these conditions are met: 1. Your Windows username has non-English characters. 2 Those characters are in a different language than the Windows “system locale”.