I have no idea how big iBasso is, but the use of the stock XMOS driver is something that most designers using this chipset do. Companies also tend to ship with the driver they tested with - even if it's not the latest. If there is a newer one, it'll likely work just fine :-)
Anyone had success installing D7 drivers on Win XP system?
I tried it with different Thesycon drivers (from Cambridge Audio, Ayre etc.) but the D7 gets no USB link.
With Vista or Win 7 it runs perfect. Easiest connection was with Ubuntu. Plug and play at it's best!
I had contact to Thesycon and they said that iBasso uses a very old driver version and that the driver isn't fitted to the device. It's the version from the XMOS evaluation package!
I think iBasso is a 2-people firm with no software specialists. Just plug and pray!