Even before the PCI security standard for applications (PABP) becomes mandatory the PCI organization has retired it. It has been replaced with a new PA-DSS standard. The PCI web site details the  changes from PABP to PA-DSS.

One of the big changes is the PA-DSS is NOT required to process credit cards unless your credit card gateway/provider requires it. This should be a huge relief to many merchants as it will allow them to negotiate with their payment provider for a reasonable timeline to get certified.