A new version of beta2 was released a couple of days ago. is this the same as the svn of that day? or is it just a few changes made on the older beta2 code?
I believe it's not. I read something on the devlist about it.
http://lists.roundcube.net/mail-archive/roundcube.dev/2006/12/168/
But the security issues would be fixed in the latest SVN I assume?
Yes, the last branch is 0.1 beta2 with the security update.