...Features multi-language support, MIME attachments, displays HTML messages.
The installation guide comes with the source code:
https://sourceforge.net/p/nocc/code/HEAD/tree/trunk/webmail/docs/INSTALL
If you encounter problems or bugs you can always try the current HEAD version:
https://sourceforge.net/p/nocc/code/HEAD/tarball?path=
Questions, bug reports or support requests are very welcome:
https://sourceforge.net/p/nocc/_list/tickets
Alternative source code repository:
https://github.com/oheil/NOCC