This document focuses on identifying and documenting additional Business Requirements to support the increased use of electronic invoicing (eInvoicing) in the Business-to-Business (B2B) market within the European Economic Area (EEA) and CEN Member states. It aims to update and extend the current standards, particularly EN 16931-1 and CEN/TR 16931-5, to better facilitate B2B transactions. Included in the Scope are: Core Invoice Model (EN 16931-1): Enhancements and adaptations to the Core Invoice Model to address specific B2B requirements while maintaining compliance with the foundational elements. Extension Methodology (CEN/TR 16931-5): Revisions and updates to the Extension Methodology to incorporate new Business Requirements and facilitate the creation of interoperable Extension Components. Integration of Additional Requirements: Identification and integration of additional sector-specific and cross-sector Business Requirements into the existing standard framework. Harmonisation with EU Parliament Work: Ensuring that the updates align with ongoing and future initiatives by the EU Parliament to support a cohesive eInvoicing strategy across the EU. Excluded from the Scope are: Detailed Implementation Guidelines: While the document provides the framework and requirements for extensions, detailed implementation guidelines for specific software solutions or bilateral agreements are not covered. Non-Standard Extensions: Extensions that do not conform to the defined methodology and are based solely on bilateral agreements without broader applicability are excluded.