[Exim] Sophos note

If running Sophos anti-virus, you should get (or at least consider getting)
version 3.78d which has a fix for an error which combined with the odd way
qmail builds bounces of MyDoom if configured to include the message let
MyDoom slip through.

One reference:
http://www.techworld.com/news/index.cfm?fuseaction=displaynews&NewsID=1023

--John