Oficial letter No. 3870/CT-TTHT dated 02 July 2013 of HCM taxation department in guidance of symbol and ordinal number of invoices
According to the official letter No.3870/CT-TTHT:
In case, in 2011, enterprises created the self-printed invoices with symbol AD/11T and prepared notification of invoice issuance for invoices from No.0000001 to 0002000. If in 2011 and 2012, enterprises have not yet used up the mentioned invoices, the remaining will still continue to be used. If in 2013, enterprises have used up the mentioned invoices, the new self-printed invoices will be created with symbol AD/13T and the invoice’s ordinal number must reset from No. 0000001.