Zen Cart has released a new, updated version. It is highly recommended that you upgrade to the latest version to keep your store secure. This update is far more complex than the previous security patches. The charge for me to do this update is $20. Just drop me an email and I’ll get your store updated as soon as possible.
If you decide to attempt this on your own, remember to create a back up of your current files and database. Read the directions and follow each step closely. You will need to disable payment, shipping and order modules before beginning.
Read more at the Zen Cart forums -> http://www.zen-cart.com/forum/showthread.php?t=153088