When you search the PCI website for validated payment applications it shows a re-validation date and an expiry date. There is also two categories of payment applications, "Acceptable for new Deployments" and "Acceptable only for Pre-Existing Deployments".
There are applications listed that are past the Expiry date. These are in the Pre-Existing Deployments section. Does this mean as long as the application was installed before the expiry date you can use it and be compliant for as long as you want and not have to upgrade to the latest version? From reading the PCI docs on this it sounds like that is the case. But that doesn't really make sense to me. Any insight from PCI experts would be helpful.