Summary: GST e-invoicing continues to require eligible registered suppliers to report specified documents to an Invoice Registration Portal (IRP) and obtain an Invoice Reference Number (IRN) and signed QR code. Notification No. 10/2023-Central Tax brought persons whose aggregate turnover exceeded ₹5 crore in a financial year from 2017-18 onwards into the mandate from 1 August 2023. Separately, a GSTN portal validation effective 1 April 2025 restricts reporting of invoices, debit notes and credit notes older than 30 days for taxpayers with aggregate annual turnover of ₹10 crore or more. These are different thresholds, and neither should be confused with the e-way bill requirement or a GSTR-1 filing deadline. This article explains the notified framework, entity and document exclusions, the operational deadline, buyer credit implications and controls for October 2026 without treating every software validation as a separate statutory penalty.
Why the distinction matters in October 2026
An enterprise may be subject to mandatory e-invoicing but not the 30-day portal restriction. Another enterprise may operate several GST registrations under one permanent account number (PAN) and incorrectly test each GSTIN separately. Both mistakes can disrupt invoicing, customer acceptance, return reconciliation and the recipient’s input tax credit (ITC). The legal starting point is Section 31 of the Central Goods and Services Tax Act, 2017 and Rule 48(4) of the CGST Rules, 2017; the portal reporting time limit is an additional operational control explained in the GSTN advisory. An IRN is not a replacement for the underlying commercial invoice, supply evidence or statutory tax-payment obligations.
The practical issue is urgent because an October 2026 tax invoice may need IRN reporting well before the associated GSTR-1 or GSTR-3B return is filed. Teams should therefore treat IRN generation as part of the invoice-release process, not as a month-end or return-filing exercise. The published TaxGuru guide to mandatory e-invoicing also distinguishes invoice issuance from reporting the document to the IRP. This article focuses on how to apply that distinction to live controls.
Statutory basis and the two turnover thresholds
The ₹5 crore threshold determines who must e-invoice
Notification No. 13/2020-Central Tax, as amended, identifies the class of registered persons subject to Rule 48(4). Notification No. 10/2023-Central Tax dated 10 May 2023 reduced the relevant turnover threshold to aggregate turnover exceeding ₹5 crore, effective 1 August 2023. The test refers to turnover in any preceding financial year beginning with FY 2017-18. Thus a fall in current-year turnover does not automatically remove the mandate when a relevant earlier year exceeded the notified limit. The threshold uses aggregate turnover, rather than taxable turnover of one branch, and requires a PAN-wide assessment of the registered person’s supplies.
Under Section 2(6) of the CGST Act, aggregate turnover broadly covers taxable supplies, exempt supplies, exports and inter-State supplies of persons having the same PAN on an all-India basis, while excluding inward supplies on which tax is payable under reverse charge and taxes themselves. A business should reconstruct the turnover computation from filed returns, financial statements and GST registration records, including multiple States. A figure exactly equal to ₹5 crore should not casually be described as ‘exceeding ₹5 crore’; the precise notification wording and the relevant historic-year data control the conclusion.
The ₹10 crore threshold governs the 30-day portal restriction
The GSTN advisory dated 5 November 2024, implemented from 1 April 2025, applies the 30-day reporting restriction to taxpayers with aggregate annual turnover of ₹10 crore and above. The official IRP’s March 2025 release notes confirm that invoices, debit notes and credit notes outside the permitted window are rejected by the system. For a document dated 1 October 2026, reporting within the stated 30-day window would ordinarily mean reporting no later than 30 October 2026 under the portal’s illustration-based counting method. The document date, not the date the accountant notices an omission, drives the validation.
The ₹10 crore figure is not a new threshold for becoming subject to e-invoicing. Taxpayers with turnover above ₹5 crore but below ₹10 crore may still be required to obtain IRNs for covered documents even though the specific 30-day portal block does not currently apply to them. The TaxGuru report of GSTN’s 30-day advisory reproduces the operative distinction. Businesses should monitor later portal advisories, but should not presume a lower threshold without a verified change.
| Compliance question | Threshold or rule | Practical conclusion |
|---|---|---|
| Mandatory e-invoice coverage | Aggregate turnover exceeding ₹5 crore in a relevant year since FY 2017-18 | Check PAN-wide historic turnover and notified exclusions |
| IRP 30-day document reporting block | AATO ₹10 crore or more, from 1 April 2025 | Report covered invoices and notes within 30 days of document date |
| Ordinary B2C sales | Outside the notified e-invoice document scope | Separate invoice and dynamic QR rules may still apply |
| GSTR-1 and GSTR-3B | Return obligations independent of IRN | Filing a return does not retrospectively generate an IRN |
Which documents and supplies are covered?
Covered documents are not every accounting entry
For an eligible issuer, the notified e-invoicing framework principally covers tax invoices for business-to-business supplies to registered recipients, relevant business-to-government transactions, exports and supplies to special economic zone (SEZ) developers or units, together with associated GST debit notes and credit notes. Deemed exports and supplies between distinct GST registrations may also require IRNs when they meet the relevant document conditions. Reporting is performed against the prescribed schema and generates a unique IRN and signed QR code. A supplier’s PDF bearing a self-created QR code is not an authenticated e-invoice merely because it looks similar.
The document test must be applied transaction by transaction. Ordinary business-to-consumer invoices, bills of supply for exempt supplies, financial or commercial credit notes that are not GST credit notes, import documents and pure job-work movement documents are not automatically covered simply because the business is otherwise e-invoice-enabled. A job worker making an independent taxable supply must still analyse that supply on its own facts. For reverse-charge supplies, the identity of the invoice issuer and whether a tax invoice is required under the applicable rules matter; it is unsafe to assume that every reverse-charge entry requires an IRN.
Entity-level exemptions must be checked before automation
The exemption framework under Notification No. 13/2020-Central Tax, as amended, covers specified classes such as banking companies and certain financial institutions including non-banking financial companies, insurers, goods transport agencies supplying road freight services, suppliers of passenger transportation services, specified cinema admission service suppliers and SEZ units. SEZ units and SEZ developers are not interchangeable: the latter are not exempt merely because they are developers. The relevant notification and any subsequent amendments must be checked for the legal status of a particular entity.
A clarification considered by the GST Council records that an exemption for a notified class of entity operates at entity level rather than only for the exempt entity’s principal line of business. For example, the status of a qualifying bank cannot be determined by treating its incidental taxable goods sales as a separate non-exempt enterprise. Equally, an ordinary commercial entity does not become exempt because one customer is a bank or an SEZ unit. A control register should record the exemption’s legal basis and responsible reviewer, rather than relying on a broad industry label in accounting software.
How to generate and validate the IRN
The supplier first prepares its invoice in its enterprise resource planning or billing system with the correct supplier and recipient GSTINs, place of supply, invoice number and date, tax rates, taxable value, HSN or SAC classification and other mandatory schema fields. It then transmits the relevant JSON to an authorised IRP. The portal validates the record, generates an IRN and digitally signed QR code, and returns the authenticated data. The supplier’s final invoice shared with the customer should display the prescribed QR code and other required particulars. IRP reporting should happen contemporaneously with issuance wherever operationally possible.
An e-invoice cannot simply be edited on the portal after authentication. IRP cancellation is subject to the portal’s limited cancellation window and full-document conditions, while commercial corrections may require a GST credit or debit note and accurate return reporting. Teams must separately verify the effect of an e-way bill already generated against the document. A wrong recipient GSTIN, duplicated document number or wrong document date may be more difficult to repair after the portal window closes. TaxGuru’s discussion of e-way bill and e-invoice changes addresses the distinction between those systems.
October 2026 examples and the risk of late reporting
Assume an eligible supplier with ₹12 crore AATO issues a covered invoice on 3 October 2026. The supplier should transmit it to the IRP immediately. Waiting until November’s accounting close could result in the portal rejecting the invoice because the 30-day limit is exceeded. The same logic applies to a qualifying debit note or GST credit note dated in October. The tax invoice date should reflect the true time-of-supply documentation; backdating or changing the date merely to bypass validation creates a separate record-integrity and potential tax risk.
Now assume a second supplier crossed ₹6 crore in FY 2023-24 but has AATO below ₹10 crore. Subject to the notification’s precise threshold test and exclusions, e-invoicing may be mandatory, while the specific 30-day validation applicable to ₹10 crore-and-above taxpayers does not apply. That is not permission to delay statutory invoice issuance or GSTR-1 reporting. The two examples show why software should maintain separate flags for ‘IRN required’ and ’30-day IRP limit applies’ rather than one generic e-invoice switch.
| Operational failure | Immediate effect | Required control |
|---|---|---|
| Historic PAN turnover omitted | Incorrect exemption from e-invoice mandate | Annual turnover matrix across all GSTINs |
| Covered invoice reported after 30 days by ₹10 crore-plus issuer | IRP rejects IRN generation | Daily exception dashboard with age of unreported documents |
| IRN generated with wrong recipient GSTIN | Customer rejection and ITC reconciliation problems | GSTIN master validation before invoice release |
| Invoice posted to GSTR-1 but never authenticated | Return filing does not cure Rule 48(5) issue | Reconcile IRP acknowledgements to invoice and GSTR-1 registers |
| GST credit note treated as a non-tax financial credit | Possible omitted IRN | Classify credit notes by legal tax effect |
Tax, customer and audit consequences
Rule 48(5) provides that an invoice issued by a person to whom Rule 48(4) applies, otherwise than in the prescribed manner, is not treated as an invoice for the purposes of the rules. That can create a material documentary problem for the supplier and for the recipient’s ITC claim under Section 16 of the CGST Act. It does not mean that every customer claim is automatically and conclusively denied in every factual setting; the applicable legal requirements, supplier’s actual compliance and available remedies must be assessed. A valid IRN is therefore a preventive control rather than merely a customer-service convenience.
A missing or defective mandatory e-invoice can also expose the supplier to proceedings under the applicable penalty provisions of the CGST Act, including Section 122 where its ingredients are satisfied. Penalties should not be quoted as a universal fixed amount without identifying the exact contravention, tax effect and statutory clause. The separate 30-day portal validation is not itself a substitute for a reasoned penalty order. Any liability for interest, late fees or tax must be traced to the relevant return, payment or invoice default rather than mechanically assumed from a rejected upload.
From an audit perspective, management should preserve original invoice data, IRP request and response logs, signed QR-code verification, cancellation records, credit-note trails, GSTR-1 reconciliation and customer correspondence. Controls should include automated alerts at days 7, 15 and 25 after document date, a maker-checker process for GSTIN changes, and a monthly exception certification. For entities with multiple GSTINs, the tax function should own the PAN-wide turnover test and the technology function should own successful IRN integration, with accountability recorded in the control matrix.
Practical action plan for October 2026
First, document the threshold test using each financial year’s PAN-wide aggregate turnover from FY 2017-18 onwards and compare the result with Notification No. 10/2023-Central Tax. Second, check whether the supplier belongs to an exempt class under Notification No. 13/2020-Central Tax as amended. Third, classify transactions by the type of GST document and recipient. Fourth, identify whether the ₹10 crore 30-day IRP validation applies and configure a warning based on actual document date. Fifth, test whether authenticated invoice data is reaching the sales register and GSTR-1 correctly.
Finally, perform a one-time October backlog scan before month-end. Isolate every covered invoice, debit note or credit note without a successful IRN, identify its age and escalate it before the reporting window closes. Do not generate substitute or backdated documents to mask the original event. Where the window has already expired, obtain case-specific advice, preserve the audit trail and consider appropriate disclosure or remedial procedures. The objective is to avoid preventable compliance failures without making unsupported claims that the GST law automatically grants an extension or a portal override.
Frequently Asked Questions
Q1. Does the ₹5 crore threshold apply separately to each GSTIN? No. The notification must be read with aggregate turnover under Section 2(6), generally requiring a PAN-wide all-India turnover assessment across registrations, subject to the statutory exclusions from the computation.
Q2. Is the ₹10 crore 30-day rule the threshold for mandatory e-invoicing? No. Mandatory coverage and the 30-day IRP validation are different tests. The ₹5 crore notification determines coverage, while the ₹10 crore rule determines whether older documents are blocked by the portal.
Q3. Do B2C invoices require an IRN? Ordinary B2C invoices are outside the currently notified e-invoice document scope. Separate invoicing, reporting and dynamic QR-code requirements must still be examined where applicable.
Q4. Are SEZ units and SEZ developers treated alike? No. The notified exemption for SEZ units should not be extended automatically to SEZ developers. Supplies made by a regular eligible supplier to an SEZ recipient can still require an IRN.
Q5. Can GSTR-1 filing replace a missing IRN? No. GSTR-1 is a return of outward supplies, whereas Rule 48(4) requires authenticated invoice issuance for the covered class. The systems are connected but legally distinct.
Q6. Can an invoice be backdated to solve an IRP error? Changing the genuine document date to circumvent a validation is not a compliant solution. Preserve records and seek a fact-specific remedy instead.
Q7. Does every rejected IRN automatically attract a fixed penalty? No. A portal rejection is a system event. Any statutory penalty requires analysis of the actual default, applicable section, evidence and legal procedure.
Key Takeaways
For October 2026, the core control is to separate the ₹5 crore e-invoice coverage test from the ₹10 crore 30-day IRP reporting restriction. Apply the PAN-wide turnover test, respect entity-level exclusions, distinguish B2B and export documents from ordinary B2C documents, and generate IRNs when invoices are issued. The best audit evidence is an invoice-to-IRP-to-GSTR-1 reconciliation with a dated exception log. Where a document is already outside the portal window, preserve facts and obtain specific legal advice rather than altering dates.
Official Sources Checked
Goods and Services Tax Council: Notification No. 10/2023-Central Tax dated 10 May 2023 and Notification No. 13/2020-Central Tax dated 21 March 2020 (as amended). GSTN advisory dated 5 November 2024, reproduced by TaxGuru, and authorised IRIS IRP release notes dated 31 March 2025. Authorised IRP FAQ on covered and excluded document types. Statutory references: CGST Act, 2017, Sections 2(6), 16 and 31; CGST Rules, 2017, Rule 48(4) and 48(5). This source check does not imply that a future GST Council proposal is already in force.
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Disclaimer: This article provides general educational information based on official GST notifications, statutory provisions and portal advisories reviewed as of 11 October 2026. Applicability depends on the registered person’s PAN-wide turnover history, legal status, transaction type, document date, portal functionality and subsequent amendments. Portal validations and published FAQs must be distinguished from the text of enacted law, and illustrative calculations are not a substitute for examining the applicable documents. Readers should verify the latest CBIC and GSTN position and seek professional advice before filing, issuing corrective documents or taking a tax position. The author and TaxGuru accept no responsibility or liability for any loss, tax demand, penalty, business interruption or other consequence arising from reliance on this article.
