HSN code digit requirement on tax invoices mandates differing HSN digit disclosure based on turnover tiers, effective from July. Registered persons must state HSN code digits on tax invoices under the Union Territory GST for Daman and Diu according to prescribed turnover bands: the lowest band is exempt, the middle band requires two digits, and the highest band requires four digits. The obligation arises under the proviso to rule 46 and takes effect from 1 July 2017.