GSTR-3B hard-locking
GSTR-3B hard-locking is the GST portal's move to freeze auto-populated GSTR-3B fields, preventing manual editing of tax liability and, progressively, ITC values.
Hard-locking removes the ability to hand-edit auto-populated GSTR-3B cells. It has no statutory basis — it is a GSTN portal change made by advisory. The outward-liability side is locked: Tables 3.1/3.1.1 from the July 2025 tax period, and Table 3.2 separately from the November 2025 tax period; correct those at source via GSTR-1A. The ITC side (Table 4) is NOT locked and no date has been announced — GSTN's 17 October 2024 advisory defers it to 'a later date', and its 8 October 2025 advisory confirms ITC auto-population is unchanged. Table 4 remains editable.
GSTR-3B has long been the summary return where liability and credit are declared. Hard-locking ends the era of overriding some of those cells — but it is worth being precise about what is actually locked, because a lot of coverage is not. It has no statutory basis: no Act, rule or notification mandates it, and Rule 61 (which governs the form and due date of GSTR-3B) is silent on editability. It is GSTN portal configuration, made by advisory. The outward-liability side is locked in two steps: Tables 3.1/3.1.1 from the July 2025 tax period, and Table 3.2 separately from the November 2025 tax period — correct either at source by filing GSTR-1A for the same period before your GSTR-3B.
The ITC side (Table 4, from GSTR-2B as shaped by the Invoice Management System) is a different story: it is not locked, and no date has been announced. GSTN's advisory of 17 October 2024 says ITC locking "will be implemented from a later date" pending "a separate advisory" — which has not issued. Its advisory of 8 October 2025 goes further: "No Change in Auto-Population of ITC ... The mechanism ... remains unchanged." Table 4 remains editable. Be wary of any specific ITC-lock date (a "July 2026 tax period" figure circulates in tax media but appears in no GSTN instrument).
The practical effect is that reconciliation must be finished upstream. If a figure is wrong, you fix the source document before filing — you can no longer patch it in 3B. This dovetails with DRC-01C: as editing goes, an unresolved 2B gap becomes a mismatch notice rather than a manual adjustment. Treat pre-filing reconciliation as the last editable moment; once the return locks, corrections belong in a later period's return (or a voluntary payment via DRC-03) — there is no GSTR-3B amendment facility.
The Recoup angle: Recoup reconciles before the return locks, so the auto-populated 3B you file is already the correct one.