This is probably OT, but how much is MIX/MMIX still used in the new books coming out? Volume1 had MIX code for everything, and IIRC by Volume3 it wasn't as per

This is probably OT, but how much is MIX/MMIX still used in the new books coming out? Volume1 had MIX code for everything, and IIRC by Volume3 it wasn't as pervasive. Does Volume4 have MMIX code for all algorithms presented?