[SI-UBL-INV-R000]-Simplerinvoicing v1.0 validation is used but will soon be obsolete, please move to Simplerinvoicing v1.1 [SI-UBL-INV-R436]-IF VAT = "AE" (reverse charge) THEN it MUST contain Supplier VAT id and Customer VAT [SI-UBL-INV-R437]-IF VAT = "AE" (reverse charge) THEN VAT MAY NOT contain other VAT categories. [SI-UBL-INV-R438]-IF VAT = "AE" (reverse charge) THEN The taxable amount MUST equal the invoice total without VAT amount. [SI-UBL-INV-R439]-IF VAT = "AE" (reverse charge) THEN VAT tax amount MUST be zero. [SI-UBL-INV-R429]-If the VAT total amount in an invoice exists it MUST contain the suppliers VAT number. [SI-UBL-INV-R445]-Currency Identifier MUST be in stated in the currency stated on header level. [SI-UBL-INV-R428]-If the VAT total amount in an invoice exists then an Allowances Charges amount on document level MUST have Tax category for VAT. [SI-UBL-INV-R434]-An allowance percentage MUST NOT be negative. [SI-UBL-INV-R435]-In allowances, both or none of percentage and base amount SHOULD be provided [SI-UBL-INV-R443]-An allowance or charge amount MUST NOT be negative. [SI-UBL-INV-R444]-AllowanceChargeReason text SHOULD be specified for all allowances and charges [SI-UBL-INV-R430]-For each tax subcategory the category ID and the applicable tax percentage MUST be provided. [SI-UBL-INV-R432]-If payee information is provided then the payee name MUST be specified. [SI-UBL-INV-R433]-If the VAT total amount in an invoice exists then each invoice line item MUST have a VAT category ID. [SI-UBL-INV-R440]-Total payable amount in an invoice MUST NOT be negative [SI-UBL-INV-R441]-If the invoice refers to a period, the period MUST have a start date. [SI-UBL-INV-R442]-If the invoice refers to a period, the period MUST have an end date. [SI-UBL-INV-R451]-Party Identifiers MUST use the PEPPOL PartyID list [SI-UBL-INV-R452]-Endpoint Identifiers MUST use the PEPPOL PartyID list.