The new release 2009.10-2 [1] is pre-installed with all security updates that have come out since the last release batch. Security updates will also be installed on first boot to prevent a window of vulnerability from opening between the time a fresh appliance is deployed and until the (daily) cron job that installs the security updates runs.

Note that Ubuntu 8.04 is a Long Term Support (LTS) release which will continue to be supported by Canonical with security updates for another 3 years (until April 2013).

All appliances will be rebuilt on top of Lucid (the new LTS) when it is released at the end of the month.

[1] http://www.turnkeylinux.org/blog/maintenance-release