In the first Book 3 draft I have on file - 13 June 2007 - it was:
"Only after 1150 AD:
Upgrade German Kn as double-based Reg Kn (I) @ 10AP if front element, 8AP if rear element All"
In the July 21 draft it had become:
"Only after 1235 AD:
Upgrade German Kn as double-based wedge of ½ Reg Kn (O) @ 12AP, ½ Reg Kn (I) @ 8AP All"
And it was still 1235 in 22 September, which is the latest draft I have on file.