Yes, there are multiple versions of the XML PunchOut standard. The most widely used version is cXML PunchOut, which is supported by most e-Procurement and ERP systems. Another common version is OCI Roundtrip, which is specific to SAP SRM e-Procurement applications. Some applications support both, but cXML is often preferred for its robustness and ease of support. It’s important to note that each e-Procurement system vendor has their own sub-versions of each iteration, customised to suit their specific business needs. Therefore, it’s important to understand which version and sub-version your customer requires to ensure compatibility.