EPIC is 100% backwards compatible with ircII because EPIC is ircII. EPIC was originally built upon the ircII 2.6 client and has maintained faithfulness to remain current up to the 2.8.2 release.
EPIC is slightly larger than ircII-4.4 (about 40k on this system), but that is mostly because of the multitude of new features, the dual ANSI/K&R compliant function headers, and the large amount of re-written code in an attempt to make ircII faster, more efficient, and more powerful.
EPIC is derived directly from IRC-II which is currently maintained by Matthew Green, and includes in whole all the additions included in the “plus” clients by Jeremy Nelson and all of the modifications in the “mod” clients by Jake Khuon. EPIC is currently maintained by EPIC Software Labs (ESL), comprised of Jeremy Nelson, Jake Kuhon, Robert Chady, and a cast of a dozen others.
You can get a copy of the EPIC client from these URLs:
If you want to mirror the EPIC client, please drop an email to Jeremy Nelson (firstname.lastname@example.org) telling him the host and directory where we can count on you to keep a copy of the current version of the EPIC client. The EPIC client takes about 450k, the help files take about 150k, and from time to time there are other patches that range from 5k to 30k in size.
A mailing list for all things related to EPIC exists. Send email to email@example.com with the words “subscribe ircii-epic” in the body (and nothing else!). This list exists for bug reports, discussion about and requests for new features, and anything else that has to do with EPIC.