Registration liability for GST hinges on aggregate turnover and lower thresholds for special category states. Registration is mandatory where a supplier's aggregate turnover in a financial year exceeds the statutory threshold, with a lower threshold for supplies from specified special category States. Persons registered or licensed under prior law on the day before the appointed day must register from the appointed day. Transfers of a registered taxable business as a going concern render the transferee or successor liable to register from the date of transfer; in sanctioned amalgamations or demergers, the transferee must register from the date the Registrar of Companies issues the incorporation certificate. Aggregate turnover includes all supplies by the taxable person, while supplies by a registered job worker after job work are treated as supplies by the principal.