Two GST Changes Went Live 36 Days Ago. One Freezes Your Return. The Other Is ₹10,000 Per Invoice.

The story

Deepak runs a mid-sized trading business in Gurugram’s Udyog Vihar. He has filed GST returns since 2017 — never missed a GSTR-3B, always deposited on time. His turnover crossed ₹6 crore in FY 2025-26.

On 20 May 2026, when his April GSTR-3B is due, he will log in and attempt to file. If his ITC claims do not exactly match the figures auto-populated in his GSTR-2B, the portal will block his filing entirely. Not flag it. Not warn him. Block it.

There is a second problem. Since 1 April 2026, every B2B invoice Deepak raised must carry an Invoice Reference Number (IRN) from the IRP. Without one, the invoice is non-compliant under Section 122 of the CGST Act — a penalty of ₹10,000 per invoice or 100% of the tax, whichever is higher. His billing software was never updated. Thirty-six days of invoices, each potentially non-compliant.

Why most owners haven’t acted yet

Both changes were announced well in advance, but between the notification and the business owner updating their process is a gap the GST system has always struggled to close. The ITC hard block is especially dangerous because it looks like a technical glitch the first time it triggers — most owners (and many accountants) assume the portal is having an issue and wait for it to resolve. It is not a glitch. It is the new normal.

Two changes, both live from 1 April 2026

Change 1 — ITC hard block: if your claimed ITC in GSTR-3B exceeds your GSTR-2B figure by even a single rupee, the portal blocks filing. The three common triggers: a supplier filed GSTR-1 late or not at all (their invoice isn’t in your GSTR-2B); an invoice-timing difference (uploaded in the next month’s GSTR-1); or a wrong GSTIN on the invoice (credit doesn’t map to you). The Invoice Management System (IMS) is the companion tool — any invoice a supplier uploads appears on your IMS dashboard, and if you take no action it is deemed accepted and flows into GSTR-2B. Unreviewed invoices that auto-flow cannot be reversed once the cycle closes.

Change 2 — e-invoicing: mandatory for AATO above ₹5 crore from 1 April 2026 (reduced from ₹10 crore). Every B2B invoice, credit note and debit note must carry a valid IRN from the IRP. It doesn’t change your invoice format — it adds an IRN-generation step before the invoice is issued to the buyer.

Deepak vs Meena — same turnover, two May 20 experiences

Both have comparable turnover and tax liability. The difference is not their numbers — it is a software configuration that took Meena’s consultant four hours to complete in March.

How to actually start — 5 steps

1. Check whether your AATO crossed ₹5 crore in FY 2025-26. On the GST portal, check your Annual Aggregate Turnover. At ₹5 crore or above, e-invoicing is mandatory from 1 April 2026; below it, not yet — but check monthly as you approach the threshold.
2. Configure your software for IRP integration today. Tally Prime, Zoho Books, Busy, MARG ERP and others already have the module — activate e-invoicing, enter your GSTIN and API credentials, and test-generate one IRN on a sandbox invoice. If your software can’t integrate, use the free government IRP at einvoice1.gst.gov.in.
3. Review your IMS dashboard at least weekly. Accept valid supplier invoices, reject incorrect ones. The critical rule: no action = deemed accepted at cycle end, and you cannot undo a deemed acceptance after the window closes.
4. Reconcile GSTR-2B with your purchase register before filing. Compare line-by-line against your GSTR-3B ITC claim. If a supplier’s invoice is in your register but not in GSTR-2B, they haven’t filed GSTR-1 — either defer that ITC to May (safer for your deadline) or ask them to file before 20 May.
5. If you’ve raised B2B invoices without IRNs since 1 April, regularise them now. Ask your GST consultant whether back-dated IRN generation is possible. Don’t wait for a notice — voluntary correction before enforcement significantly reduces penalty exposure.

Your GSTR-3B is not just a return — from April 2026 it is a compliance statement the portal can validate in real time against your supplier data.

Key takeaways

But here is the other side…

Taken together, the ITC hard block and IMS are a genuine simplification for businesses with disciplined purchase registers. In the old system, mismatches could accumulate for months before a reconciliation statement or scrutiny notice surfaced them — often as large, unexpected demands. The new system surfaces mismatches in real time, every month. A business that reviews IMS weekly and reconciles GSTR-2B before filing will almost never face a disputed ITC claim. Painful in the first few months of transition — structurally cleaner than what it replaced.

The portal is not having a glitch — this is the new system

When Deepak’s filing is blocked on 20 May, his first instinct will be to ask if the portal is down. It is not — this is the new filing experience. The IMS review, the GSTR-2B reconciliation before filing, and IRP integration for e-invoicing are not temporary adjustments; they are the permanent operating reality for every GST-registered business above the relevant thresholds from 1 April 2026. Businesses that update their processes in May will file June smoothly. The ones that don’t will repeat this exercise — with compounding interest — every month until they do.

WeConsult India manages monthly GST compliance — GSTR-1, GSTR-3B, IMS dashboard review, GSTR-2B reconciliation and e-invoicing setup — for businesses across Gurugram’s Udyog Vihar, Sector 37 and IMT Manesar. If your April 2026 GSTR-3B is at risk of blocking, contact us before 20 May.

Stay compliant. Stay protected. — WeConsult India