EPIC4 is a new direction in ircII development. No longer is EPIC 100% 
backwards compatible with ircII, but instead those things where 
compatibility is undesirable have been found and fixed. No gratuitous 
incompatibilities have been added, but lots of new code has been added to 
make EPIC the best ircII client available.

EPIC no longer shares any file names with ircII, so they should happily
co-exist.

WWW: http://www.epicsol.org/