GST notification amendment extends the specified date in the proviso and applies retrospectively from 30 June 2023. The proviso in the earlier Assam GST notification is amended by replacing the date '30th day of June, 2023' with '31st day of August, 2023'. The amendment is made under section 128 of the Assam Goods and Services Tax Act, 2017, on the recommendation of the Council, and is deemed to have come into force from 30th June, 2023.