To use SplitsTree you are required to obtain a license from
here.
Program installers:
splitstree_macos_4_13_1.dmg (MacOS X)
splitstree_windows_4_13_1.exe (Windows-XP)
splitstree_windows-x64_4_13_1.exe (64-bit, Windows 7)
splitstree_unix_4_13_1.sh (Linux or unix)
Manual.
To find out what has changed in recent versions, see the
release notes.