Extension of statutory compliance date by notification under statutory power, altering the deadline set in the earlier tax notification. Amendment substitutes the deadline in the proviso to paragraph 2 of Notification No. 21/2019 State Tax with a later date, effected under the statutory power conferred by the Mizoram Goods and Services Tax Act, 2017 and issued as Notification No. 35 of 2019 State Tax, noting the principal notification and a prior amendment.