A vulnerability in the Eggdrop and Windrop bot has been found which prompts a new release.
The vulnerabilitiy is present in both latest versions of the bot software 1.6.19 which has been released back in April 2008.
A posting on the Full Disclosure mailinglist goes into more detail, describing how one can at least crash vulnerable bots:
One possible exploit anyone can send to the IRC server to crash eggdrop:
PRIVMSG eggdrop :\1\1
The only resolution at this time is upgrading old bots with the provided fix.