diff --git a/ReactCommon/fabric/uimanager/Differentiator.cpp b/ReactCommon/fabric/uimanager/Differentiator.cpp
index 87f92990450..a689d51d9db 100644
--- a/ReactCommon/fabric/uimanager/Differentiator.cpp
+++ b/ReactCommon/fabric/uimanager/Differentiator.cpp
@@ -5,7 +5,7 @@
 namespace facebook {
 namespace react {
 
-void calculateMutationInstructions(
+static void calculateMutationInstructions(
   TreeMutationInstructionList &instructions,
   SharedShadowNode parentNode,
   SharedShadowNodeSharedList oldChildNodes,
@@ -154,5 +154,33 @@ void calculateMutationInstructions(
   instructions.insert(instructions.end(), downwardInstructions.begin(), downwardInstructions.end());
 }
 
+
+void calculateMutationInstructions(
+  TreeMutationInstructionList &instructions,
+  SharedShadowNode oldRootShadowNode,
+  SharedShadowNode newRootShadowNode
+) {
+  // Root shadow nodes must have same tag.
+  assert(oldRootShadowNode->getTag() == newRootShadowNode->getTag());
+
+  if (*oldRootShadowNode != *newRootShadowNode) {
+    instructions.push_back(
+      TreeMutationInstruction::Replace(
+        nullptr,
+        oldRootShadowNode,
+        newRootShadowNode,
+        -1
+      )
+    );
+  }
+
+  calculateMutationInstructions(
+    instructions,
+    oldRootShadowNode,
+    oldRootShadowNode->getChildren(),
+    newRootShadowNode->getChildren()
+  );
+}
+
 } // namespace react
 } // namespace facebook
diff --git a/ReactCommon/fabric/uimanager/Differentiator.h b/ReactCommon/fabric/uimanager/Differentiator.h
index 7eb9fa332ff..c1d7a8b1d4e 100644
--- a/ReactCommon/fabric/uimanager/Differentiator.h
+++ b/ReactCommon/fabric/uimanager/Differentiator.h
@@ -15,9 +15,8 @@ namespace react {
  */
 void calculateMutationInstructions(
   TreeMutationInstructionList &instructions,
-  SharedShadowNode parentNode,
-  SharedShadowNodeSharedList oldChildNodes,
-  SharedShadowNodeSharedList newChildNodes
+  SharedShadowNode oldNode,
+  SharedShadowNode newNode
 );
 
 } // namespace react
diff --git a/ReactCommon/fabric/uimanager/ShadowTree.cpp b/ReactCommon/fabric/uimanager/ShadowTree.cpp
index 32a7870d96a..30b24643864 100644
--- a/ReactCommon/fabric/uimanager/ShadowTree.cpp
+++ b/ReactCommon/fabric/uimanager/ShadowTree.cpp
@@ -69,8 +69,7 @@ void ShadowTree::complete(UnsharedRootShadowNode newRootShadowNode) {
   calculateMutationInstructions(
     instructions,
     oldRootShadowNode,
-    oldRootShadowNode->ShadowNode::getChildren(),
-    newRootShadowNode->ShadowNode::getChildren()
+    newRootShadowNode
   );
 
   if (commit(newRootShadowNode)) {
diff --git a/ReactCommon/fabric/uimanager/TreeMutationInstruction.cpp b/ReactCommon/fabric/uimanager/TreeMutationInstruction.cpp
index 42882ee6cfc..fd728dd7a41 100644
--- a/ReactCommon/fabric/uimanager/TreeMutationInstruction.cpp
+++ b/ReactCommon/fabric/uimanager/TreeMutationInstruction.cpp
@@ -82,10 +82,8 @@ const TreeMutationInstruction TreeMutationInstruction::Replace(
   SharedShadowNode newChildNode,
   int index
 ) {
-  assert(parentNode);
   assert(oldChildNode);
   assert(newChildNode);
-  assert(index != -1);
 
   return TreeMutationInstruction(
     Replacement,