If you’re running my Zen Cart Discount Preview extension and displaying Group Discounts in the cart, when you upgrade to Zen Cart 1.3.8, please be sure to apply the patch described in the help. It is required because of an internal change made to Zen Cart in the 1.3.8 release.
… and if you’re not running Discount Preview, you should be! It’s a great mod, and the proceeds from it help fund the free software I create for Zen Cart, like Quantity Discounts and Better Together. Thank you!