There are two current generations: EPIC4 and EPIC5. They are not generally interchangeable; you should use whichever one your script requires. Most OS distributions have EPIC4 and EPIC5 binary packages available.
EPIC, as shipped by us, only is released as source code, which you can get via HTTP, FTP and Git. The latest releases are available here:
The EPIC5 and EPIC4 source code repository is available through anonymous git: