Singapore to Reclassify GST Business Rules as
Fatal Errors from May 2026

The Infocomm Media Development Authority (IMDA) has announced a significant compliance update to the InvoiceNow (Peppol) framework, which will take effect in May 2026. Several Goods and Services Tax (GST) business rules for electronic invoices and credit notes will be reclassified from warnings to Fatal errors, meaning that any document failing these validations may be rejected outright by the Peppol network.

Key Impact

This change affects all B2B und B2G transactions processed through the InvoiceNow network. Businesses must update their invoice and credit note data mapping to fully comply with the affected GST rules before the deadline to avoid disruptions in transaction processing.

Affected GST Business Rules

BR-106-GST-SG : For specified GST Category codes (SR, SRCA-S, SRCA-C, ZR, SRRC, SROVR-RS, SROVR-LVG, NA), invoices/credit notes must include the seller’s address line 1 and postal code.
BR-107-GST-SG : For the same GST Category codes, invoices/credit notes must include the buyer’s address line 1 and postal code.
BR-108-GST-SG : Must contain a Universally Unique Invoice Identifier (UUID).
BR-109-GST-SG : UUID must be formatted according to the official standard.
BR-112-GST-SG : Must include the seller’s legal registration identifier.
BR-113-GST-SG : If currency is not SGD, must include an Accounting currency code with the value “SGD”; if currency is SGD, this field must not be provided.
BR-111-GST-SG : For credit notes, must include a note stating the reason for the credit.

Transition Timeline

Starting July 2025, Access Point (AP) providers will be required to report participants receiving these warning statuses to the IMDA. This measure is intended to improve compliance ahead of the May 2026 enforcement date.

Next Steps for Businesses

Organizations using the InvoiceNow network should conduct immediate validation checks against these rules and implement necessary system changes well before the enforcement deadline to avoid operational disruptions.

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