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 and 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

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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