I have some barcode fonts which print perfectly using an external PDF printer, however invoices generated by the internal PDF engine are missing barcodes. The following is in the log.
SErver is linux, clients - windows.

2017-04-13 17:54:11 VK PDF Error: 4191
2017-04-13 17:54:11 VK PDF error embedding font: fonts/ADVC128B.TTF: Unsupported
ttf format.
2017-04-13 17:54:11 VK Times-Roman will be used instead.