The current version the papiNet standard is V2.40 if using Namespace and V2.31 if using non-Namespace.   These version are backward compatible to V2.0. They are not backward compatible to any release of V1.  Any subsequent publication of updates will contine to be applied to V2.31 and V2.40 in the form of new build dates. There are currently no plans to upgrade the standard to a version 3.