Here is a list of all the new part numbers from HPE. There is no new part number for LTO-4 because HP has stopped production and the tapes can no longer be ordered from HPE.
Generation | Old Part Number | New Part Number |
*Probably Sony OEM | * Probably Fuji OEM | |
LTO Ultrium Gen 5 | C7975A | C7975AA |
LTO Ultrium Gen 6 | C7976A | C7976AA |
LTO Ultrium Gen 7 | C7977A | C7977AA |
LTO Ultrium Gen 8 | Q2078A | Q2078AA |
LTO Ultrium Gen 9 | Q2079A | Q2079AA |
It is (probably) to distinguish Sony LTO stock from Fuji LTO stock
It may surprise some, but HPE - the largest seller of branded LTO tapes - does not make the tapes themselves. They get them OEMed from Sony and Fuji. Fuji has gone from strength to strength with its BaFe technology used for all tapes from LTO-7 on, but Sony also makes tapes and the quality, performance and reliability of the tapes made by Fuji and Sony are the same.
We have found that the tapes ending in AA are made by Fuji and the tapes ending in Single A are made by Sony. However this is a matter of logistics, not service, as the part number on the inside of the box of 5 is still a single A. So mostly HPE is only trying to distinguish the master cartons based on the origin of the factory for their logistics purpose.