Yes, they just released version 5.4.21 but a bug was found...
I, personally, am running 5.4.13 in two places where there are modifications in one of them.
?? Someone needs to update this: http://sourceforge.net/projects/vpopmail/
Latest News
* vpopmail 5.4.6 addresses SQL injection vulnerability. 2004-08-19
/me shrugs. I go here:
http://sourceforge.net/project/showfiles.php?group_id=85937
But then I am on the vpopmail list too....