The old style of caves always get cut off when they reach Y=0
Linked issues
is duplicated by 9
MC-214964
old caves don't generate below y=0
Resolved
MC-215056
there are no old caves only waterfilled new caves above level 0
Resolved
MC-215265
Old cave generation stops at y=1
Resolved
MC-215657
Not all Cave types generate at all underground levels
Resolved
MC-215860
Older caves don't generate below Y1
Resolved
4 more links
I've done some playing around and I've found that the actual limit is y=2, it doesn't generate from y=1 downwards