The Atheme IRC Platform is a discontinued IRCv3.1-compliant set of middleware for IRC networks. It is not being developed anymore, but 0day patches may be supplied on GitHub on a "best-effort" basis.
It is typically combined with an IRCv3.1 compliant IRC daemon. Find out more about IRCv3 at ircv3.net.
Older versions all the way back to version 0.1 in 2005, are available in the downloads directory.
At the present time, we know of the following projects that have officially declared themselves as forks. Atheme does not warrant the suitability of any forks, however individual maintainers may have their own opinions.