Spain has published Order HAC/1028/2026 of 2 October 2026 in the Official Gazette, which establishes the technical and functional requirements for Spain's public electronic invoicing (e-invoicing) solution (solución pública de facturación electrónica). It implements the regulations set out under Royal Decree 238/2026 of 25 March 2026, which provided for the introduction of new mandatory e-invoicing requirements for the B2B transactions of businesses and professionals. As per the Royal Decre…