GSTN issued very important Advisory on the Implementation of mandatory mentioning of HSN codes in GSTR-1 & GSTR-1A

Implementation of Phase-III: Effective from the January 2025 return period, Phase-III introduces mandatory selection of HSN codes from a dropdown menu for reporting in Table 12 of GSTR-1 and GSTR-1A, replacing manual entry.
Bifurcation of Table 12: Table 12 has been divided into two separate tabs—B2B Supplies and B2C Supplies—allowing taxpayers to report supplies separately, with validations introduced to ensure consistency in reported values.
Validation Mechanism: Initial validations for B2B and B2C supplies will operate in warning mode, meaning discrepancies will not block filing GSTR-1 or GSTR-1A, but taxpayers will receive alerts for mismatches.
New Functionalities: Enhancements include a button to download an updated list of HSN and SAC codes, and a searchable feature for “Product Name as in My Master,” which auto-populates relevant fields based on user selections.
Future Phases: Phase 4 details will be communicated later, indicating ongoing updates and enhancements to the GST reporting process.