The December Shift: 3 Critical GSTN Advisories Changing Compliance in 2026

If December 2025 felt unusually busy on the GST front, it wasn’t just the year-end rush. The Goods and Services Tax Network (GSTN) issued a flurry of significant advisories that fundamentally change how taxpayers interact with the portal moving forward.

As we enter 2026, the theme is clear: Automation over manual intervention, and hard validation over soft warnings.

The days of “fixing it later in GSTR-3B” are rapidly disappearing. The system is tightening its grip on data consistency between returns and ledgers. Below is a consolidated analysis of the three crucial advisories issued in December 2025 that every business and tax professional must action immediately.

1. The GSTR-3B “Hard Lock”: Table 3.2 is Now Non-Editable

(Advisory dated 05.12.2025)

This is perhaps the most immediate operational change. For years, taxpayers used Table 3.2 of GSTR-3B to manually adjust details of inter-state supplies made to unregistered persons, composition dealers, and UIN holders.

The Change: Effective from the November 2025 tax period, Table 3.2 is hard-locked. The data is auto-populated directly from your GSTR-1 (or IFF/GSTR-1A) and cannot be manually edited in GSTR-3B.

The CA’s Take: If your auto-populated figures in GSTR-3B are wrong, you cannot force-correct them there. You must now correct the source data. This means filing or amending Form GSTR-1A or correcting it in the subsequent month’s GSTR-1. Accuracy in GSTR-1 reporting is no longer optional; it is critical for accurate tax payment.

2. Rule 10A: Auto-Suspension for Missing Bank Details

(Advisory dated 05.12.2025)

GST registration is easier than ever, but compliance post-registration is stricter. Rule 10A requires furnishing valid bank account details within 30 days of registration or before filing the first GSTR-1/IFF.

The Change: The system has moved from passive non-compliance to active enforcement. GSTN will now automatically suspend registrations that have failed to comply with Rule 10A within the timeline.

The CA’s Take: New registrants often overlook this step. Check your portal status immediately. If your registration is suspended due to this rule, furnishing the bank details should trigger an automatic revocation of suspension (subject to validation). Do not let a simple data entry omission halt your business operations.

3. Urgent Alert: Negative Ledger Balances Will Face “Hard Blocking”

(Advisory dated 29.12.2025)

This is a ticking clock for many taxpayers. Currently, if you have a negative balance in your Electronic Credit Reversal Statement (reclaiming more than reversed) or your RCM Liability Statement (claiming more RCM ITC than liability paid), the portal shows a “Warning.”

The Change: The advisory explicitly states that this “Warning” will shortly be converted into a “Hard Blocking” validation. You will be prevented from filing returns if these ledgers show negative balances.

The CA’s Take: This requires immediate action. Run your ledger reports today.

• If you have excess RCM ITC claimed: You must pay the corresponding liability in Table 3.1(d).
• If you have excess Reclaimed ITC: You must reverse the excess in Table 4(B)(2) of GSTR-3B. Regularize these accounts before the hard block is implemented, or your filing cycle will grind to a halt.

Conclusion: The Era of Real-Time Compliance

These three advisories signal an end to the era of retrospective corrections. The GST portal is becoming an active auditor, preventing errors (and manipulations) at the source rather than flagging them later.

Businesses must upgrade their internal accounting processes to ensure data is accurate before it hits GSTR-1. The cost of carelessness is about to get much higher.