diff --git a/zip-0221.html b/zip-0221.html
index 9d9222b8..2526221e 100644
--- a/zip-0221.html
+++ b/zip-0221.html
@@ -398,7 +398,8 @@ License: MIT
return ZcashMMRNode(
left_child=left_child,
right_child=right_child,
- hashSubtreeCommitment=H(left_child.serialize() + right_child.serialize()),
+ hashSubtreeCommitment=H(left_child.serialize() + right_child.serialize(),
+ left_child.consensusBranchId),
nEarliestTimestamp=left_child.nEarliestTimestamp,
nLatestTimestamp=right_child.nLatestTimestamp,
nEarliestTargetBits=left_child.nEarliestTargetBits,
diff --git a/zip-0221.rst b/zip-0221.rst
index a927baac..4a488856 100644
--- a/zip-0221.rst
+++ b/zip-0221.rst
@@ -405,7 +405,8 @@ Tree nodes and hashing (pseudocode)
return ZcashMMRNode(
left_child=left_child,
right_child=right_child,
- hashSubtreeCommitment=H(left_child.serialize() + right_child.serialize()),
+ hashSubtreeCommitment=H(left_child.serialize() + right_child.serialize(),
+ left_child.consensusBranchId),
nEarliestTimestamp=left_child.nEarliestTimestamp,
nLatestTimestamp=right_child.nLatestTimestamp,
nEarliestTargetBits=left_child.nEarliestTargetBits,