Uni 31-10-2016 - Guidance on sample ordinal number in a kind of invoice

According to official letter 4695/TCT-CS:

Invoice symbol and name of invoice printing entity are compulsory information in an invoice. Therefore, when ordering to print invoices in the second time, if the company changes the printing entity and invoice symbol, the company’s sample ordinal number in a kind of invoice must be changed in compliance with Circular 39/2014/TT-BTC.