Registration threshold: suppliers exceeding prescribed turnover must register; specified classes must register irrespective of threshold. Every supplier making taxable supplies is liable to be registered in the State from which supplies are made where aggregate turnover in a financial year exceeds the prescribed threshold, except where such turnover comprises only supplies not liable to tax. Persons already registered under earlier laws must be registered from the appointed day, and transferees on business transfer or court sanctioned amalgamation/demerger are liable from the date of transfer or issuance of the certificate of incorporation. Certain categories must register irrespective of the threshold, including inter State suppliers, casual and non resident taxable persons, reverse charge payers, agents, input service distributors, electronic commerce operators and aggregators.