After a successful public review at the end of 2019, the VTL Task Force and the SDMX Technical Working Group have upgraded the SDMX 2.1 technical specifications in order to adopt the Validation and Transformation Language (VTL), version 2.0, published in 2018.

Thanks to these improvements, SDMX users will be enabled to write VTL programs for validating and transforming SDMX data, to store these programs in a SDMX metadata registry, and to exchange them through SDMX standard messages, along with the definition of the involved data.

This upgrade consists essentially in the addition of some new specifications for the management of VTL, leaving all the previous and already existing specifications unchanged. As a result, the existing SDMX 2.1 usages are not impacted. SDMX versions lower than 2.1 do not support VTL.

The additional parts relevant to VTL are in Section 2 (Information Model), Section 3A (SDMX-ML: XML formats), Section 3B (SDMX-ML: XML Schema, Samples), Section 5 (Registry Specifications), and Section 6 (Technical Notes). The SDMX 2.1 technical specifications include now a new revision of these parts. The VTL remains not supported in the UN/EDIFACT SDMX formats (Section 4) and in the SDMX SOAP web service interface. Please take note also that the SDMX REST and SOAP interfaces are no longer maintained in the Section 3B (WADL and WSDL parts) and that the REST interface, as improved for VTL, can be found at https://github.com/sdmx-twg/sdmx-rest.