Based on the fact that we know one of the prefixes is CDY (not CDX, as someone perceived, unless CDX is designated for test notes), i bet the first prefix will likely be CDG, and the FF* series will follow suit.
After seeing a report of FFB in recent days, it might imply that printer letters A, B, C and the yet-to-be used D continue being defunct, and we may see FFA are the debut prefix.
We'll find out in the coming days.
