[Exim] Which version for SMTP AUTH

Am I being really dumb, or do I have the wrong version of Exim? I'm running the
3.03 RPM from RedHat, and can't seem to find any mention of the SMTP AUTH
option. Do I need to recompile it (which isn't a problem) or is it a different
version (CVS HEAD?) that I need?

Cheers,
Phil