I’ve look long and hard magnified at the A (MkI) and B (MkII) boards and I can see the digital input board is different, and the middle of the dac/output board on each channel after the dacs U1 and U2 has a new opamp U13 and a couple of smd resistors R55 R59 R54? to the left.
A (MkI) http://www.superbestaudiofriends.org/index.php?attachments/yggdrasil-v1-jpg.11969/
B (MKII) http://www.superbestaudiofriends.org/index.php?attachments/yggdrasil-v2-jpg.11970/
BTW are all new and B stock Yggy now sold the new B (MkII) version?
Chewers George