[bgaluszka]

Worth noting that it's not maintained anymore http://www.cis.upenn.edu/~bcpierce/unison/status.html

[the_why_of_y]

Actually your link says just that nobody is paid to maintain it.

"It will continue to be maintained and supported for the foreseeable future, and we occasionally release new versions with bug fixes, improvements (sometimes large ones), and contributed patches."