Key GST notifications effective from 1 April 2023 — e-invoicing threshold cuts, HSN reporting, sequential returns and what holds in FY 2026-27.
From 1 April 2023, several GST notifications came into effect that reshaped how taxpayers approach e-invoicing, returns and HSN reporting. Three years later, in FY 2026-27, these changes have become standard operating practice and have been deepened by Finance Act 2026. This guide refreshes the key 1 April 2023 notifications and explains what they mean for businesses today.
Why 1 April 2023 Was a Milestone
The CBIC has historically used 1 April as a transition date for major GST changes. From 1 April 2023, the e-invoicing threshold was reduced, HSN reporting requirements tightened, late fee structures rationalised and the new financial year compliance cycle aligned with new return filing utilities. These changes formed the base on which subsequent budget cycles have built.
Key Notifications Effective 1 April 2023
- E-invoicing mandatory for taxpayers with aggregate turnover above ₹5 crore in any preceding FY
- HSN code at six digits for taxpayers above ₹5 crore turnover in B2B invoices
- Late fee rationalisation for GSTR-9 annual return for small taxpayers
- Amnesty schemes for GSTR-4, GSTR-9 and GSTR-10 non-filers from 31 March 2023 notifications
- Time limit under Section 62 for filing returns to deem assessment orders withdrawn
- Sequential filing of GSTR-1 and GSTR-3B strictly enforced
E-Invoicing Threshold Reductions
The drop in the e-invoicing threshold to ₹5 crore aggregate turnover was the single most operational change of April 2023. Lakhs of MSMEs that had never used IRP systems suddenly had to integrate billing software with the Invoice Registration Portal. In subsequent years, CBIC has further reduced this threshold and is moving toward universal e-invoicing for B2B supplies above prescribed limits notified by CBIC.
HSN Reporting and Return Quality
Six-digit HSN reporting in B2B invoices forced sharper product classification across industries. It also enabled cleaner analytics for the GSTN, which has fed automated risk scoring and notice generation under the Form DRC-01B and DRC-01C frameworks introduced later. In 2026, taxpayers above the prescribed limit must report HSN codes in line with the current CBIC notification, with mismatches against GSTR-1 often triggering DRC notices.
How Compliance Has Evolved by 2026
Finance Act 2026 and successive CBIC notifications have continued the direction set in April 2023 — lower e-invoicing thresholds, tighter HSN discipline, sequential return filing, and structured dispute resolution under Section 128A. Sandbox testing for the GSTR-1A amendment return, auto-population of GSTR-3B from GSTR-1 and IMS-based ITC matching are now part of the regular compliance cycle.
Action Points for Businesses in 2026
- Reconfirm whether your turnover crosses the prevailing e-invoicing threshold notified by CBIC
- Validate HSN code masters against the latest GSTN classification
- Reconcile GSTR-2B input credits with books using the Invoice Management System
- Settle eligible pre-2024 disputes under Section 128A
- Train teams on sequential filing and amendment return workflows
Aadhaar Authentication for New Registrations
From 2023 onwards, CBIC has progressively rolled out biometric Aadhaar authentication for new GST registrations in high-risk states. In 2026, applicants in identified states must visit a GST Suvidha Kendra for biometric verification before registration is granted. This has materially reduced fake registrations and ITC fraud but has also extended the time-to-registration for genuine applicants, who should plan their go-live dates with a buffer.
Invoice Management System and ITC Discipline
The Invoice Management System (IMS), introduced by GSTN, allows recipients to accept, reject or keep pending each invoice that appears in their GSTR-2B. In 2026, IMS is the primary tool for ITC matching and dispute prevention. Taxpayers must train AP teams to handle IMS actions before each return cycle so that disputed invoices are not silently locked into the credit ledger or carried forward into reconciliation issues.
E-Way Bill, E-Invoice and Reconciliation Interplay
Since 2023, the operational triangle of GSTR-1, e-invoice IRP data and e-way bill data has tightened materially. By 2026, the GSTN cross-references these data sources at the invoice level. A mismatch between the e-invoice IRN reported in GSTR-1 and the e-way bill issued against the same invoice can lead to ITC denial for the recipient and notices for the supplier. Build a monthly tri-reconciliation between IRN data, e-way bill data and GSTR-1 to ensure all three sources tell the same story.
Conclusion
The GST notifications effective from 1 April 2023 set the direction that CBIC has pursued ever since — lower thresholds, tighter HSN discipline and stronger return-level controls. In FY 2026-27, businesses must read these legacy notifications alongside the current GSTN circulars to operate confidently. Treat April changes each year as the starting point for compliance planning, not the end of it.
