The authority, through Notice RNC No. 4-01-50625-4, informed taxpayers classified as Large Local and Medium that, effective November 1, 2026, they must exclusively issue electronic invoices using electronic tax receipt numbers (e-CF) of type “E”. Consequently, type “B” non-electronic tax receipt number sequences will remain valid only through October 31, 2026, and may thereafter be used solely in duly declared contingency scenarios. Taxpayers should also note that the non-exclusive use of electronic invoices constitutes a tax infraction.