This is a follow-up to our earlier Fawtara alert. On August 9, 2026, the Oman Tax Authority (“OTA”) issued Decision No. 189/2026, amending the Executive Regulations of the VAT Law (Decision No. 53/2021, issued under Royal Decree No. 121/2020) to give the Fawtara programme a formal legal footing for the first time. Until this decision, the four-phase rollout existed only as an OTA administrative announcement, with no regulation behind it. That has now changed and go-live dates have moved. This alert focuses on what is new; the core mechanics we covered previously—the five-corner model, ASP roles, and format standards—remain valid and are referenced only where the new announcements affect them.¹

1. A Legally Binding Timeline, Set By Threshold Not Cohort

Decision No. 189/2026 does not set administrative phase dates; it commences in two tranches, keyed to an annual supplies’ threshold of OMR 5 million. In practice, a business now reads its own commencement date based on its own figures rather than waiting to be assigned to a phase. Note, however, that OTA has not withdrawn its published four-phase schedule, so two sets of dates currently sit side by side.

Note: As at August 17, 2026, the OTA's published e-Invoicing FAQ page still displays the earlier four-phase schedule (Aug 2026/Feb 2027/Aug 2027/Feb TBA) and had not yet been updated to reflect Decision No. 189/2026. Businesses should plan against the commencement dates in the Decision, not the FAQ. 

2. What The Decision Is Reported To Change²

• Tax invoices must be issued in an approved, secure electronic format that preserves integrity and is retained, with a unique number for each invoice. Once the duty applies to a business, paper invoices, PDF files, and emailed invoice images will no longer qualify as valid tax invoices. One carve-out survives: OTA states that after implementation, B2C invoices may still be issued on paper in addition to the prescribed electronic format.
• Simplified (B2C) tax invoices follow the same dates as standard invoices. OTA states plainly in its FAQ that B2C will be implemented at the same time as B2B and B2G, so Oman is not deferring consumer invoicing to a later phase.
• OTA is reported to be required to publish the list of companies licensed to provide e-invoicing services, rather than this being maintained only as a portal listing.
• Responsibility for system security—breach protection, failure and emergency procedures, and data recovery—is reported to sit with the taxpayer rather than the service provider. This is consistent with OTA's existing FAQ position that responsibility for invoice compliance, storage, and archiving rests with the taxpayer, although the FAQ separately requires accredited service providers to meet confidentiality and data protection requirements in their own right.
• A new Article 143 bis 2 is reported to allow the Chairman of the Tax Authority to exempt a taxpayer from issuing electronic tax invoices for a period determined by the Authority, on application supported by documents and acceptable reasons, conditional on that taxpayer continuing to file returns and pay tax within the statutory deadlines. This is the first formal exemption route for the programme. It is taxpayer-specific: OTA's FAQ states there are no industry exceptions.
• A further provision is reported to allow OTA to prescribe additional data that must appear on the tax invoice. For ERP scoping, this is the most consequential item in the Decision, because it leaves the mandatory field set open to extension by an administrative act.

3. Penalties And Enforcement

• No penalty schedule specific to e-Invoicing/Fawtara non-compliance has been published yet.
• The general VAT Law (Article 100, Royal Decree [LN1] 121/2020) already penalizes deliberately refraining from issuing a required tax invoice, with imprisonment of 2 months to 1 year and/or a fine of OMR 1,000–10,000, doubled for repeat offences. This predates Fawtara and is not an e-Invoicing-specific penalty. Practitioners should note that a competing citation is circulating in the market, attributing e-invoicing penalties to Article 202 of the Executive Regulations at OMR 500–5,000; we have not reconciled the two against the Arabic text.
• No grace period has been announced. OTA's FAQ states that all companies must complete onboarding by the rollout dates communicated to them and describes its transition support as advance contact at least six months before onboarding, together with clarification sessions. That is preparation support, not enforcement forbearance, and should not be planned around as though it were.

4. Technical Specifications Now Finalized

• PINT OM Billing v1.0.1 (Invoice / Credit Note) and Self-Billing v1.0.1, both marked Final on July 29, 2026, and aligned to PINT General 1.1.3.
• The Oman Tax Data Document (TDD) v1.0.1, also Final on July 29, 2026, reported to OTA at Corner 5.
• A deterministic UUIDv5 methodology under RFC 9562, using a fixed namespace. The Invoice UUID (BTOM-002) is derived from the seller identifier and its scheme, the invoice type code, invoice number, invoice date, and the tax and gross totals. The Seller UUID (BTOM-004) uses a different input string again, including the QR version, seller name, VAT identification number and a timestamp—the two are not interchangeable.
• A confirmed QR code structure (TLV fields, Base64-encoded, capped at 700 characters) for B2C full and simplified invoices and for profit-margin invoices, carrying the Seller UUID for verification. Note that the QR code is generated by the taxpayer at Corner 1 and is required only on the human-readable invoice, not on the e-invoice itself.
• Message-Level Status (MLS) exchange requirements with defined response codes and service-level timings. The MLS on the invoice runs between the two service providers (C3 to C2); the MLS on the Tax Data Document runs from OTA at Corner 5 back to the submitting access point.
• Two changes in the 29 July release will break existing builds and warrant immediate attention. Rule IBR-002-OM now requires an RFC 4122 version 5 UUID for the Invoice UUID and no longer accepts version 4. Rule IBR-173-OM, which previously tested the Seller UUID only against a permissive pattern of letters, digits, and dashes, now enforces proper UUID structure. Any pilot built up against the earlier specification should be re-tested.

5. What Has Not Changed

• The underlying five-corner exchange model, ASP-mediated delivery, and OTA's role at Corner 5 remain as previously briefed.
• The archiving obligation is unaffected: retention runs for ten years under the VAT Law, extending to fifteen years for tax invoices, accounting records, and customs documents relating to real estate. OTA confirms that responsibility for storing and archiving e-invoices sits with the taxpayer.
• Input VAT recovery rules are unchanged, and the timing point is easily overstated. OTA ties the switch to the end of the programme, not to the individual buyer's date: only once all rollouts have been concluded and all taxpayers have integrated must every invoice be an e-invoice to support an input VAT claim. In the interim, a buyer receiving an invoice from a seller not yet in a rollout can continue to recover under existing eligibility rules.

6. How can A&M help

7. Recommended Immediate Actions

• Confirm your entity's (and each VAT-grouped entity's) annual supplies against the OMR 5 million threshold to identify which commencement date applies. Do not wait for direct OTA notification.
• Where a genuine case exists for more time, begin preparing an exemption application well ahead of your go-live date.
• Finalize your Accredited Service Provider (ASP) selection and obtain written confirmation that their build aligns with the Oman Solution Reference Architecture v1.0.3 (July 27, 2026) and the PINT OM and TDD v1.0.1 artefacts of July 29, 2026, including the two revised UUID validation rules.
• Begin ERP gap analysis now against the finalized technical architecture rather than waiting for the gazetted text—remediation on legacy or customized ERP platforms can take 6–12 months.
• Monitor the Official Gazette for the published text of Decision No. 189/2026, and the OTA portal for an updated FAQ reconciling the four-phase schedule with the Decision's commencement dates.
• Engage us for an impact assessment, ASP selection support, or exemption-application guidance.

Sources

[1] This alert is based on OTA Decision No. 189/2026 (announced August 9, 2026) and the Final Oman Solution Reference Architecture v1.0.3 (July 27, 2026), together with public reporting as of August 17, 2026. We will issue a further update once the gazetted text of the Decision and a revised OTA FAQ are published.

[2] The provisions below are drawn from OTA's public statements and press reporting on Decision No. 189/2026.