diff --git a/backend/ReactSymbols.js b/backend/ReactSymbols.js
deleted file mode 100644
index a049c679a8..0000000000
--- a/backend/ReactSymbols.js
+++ /dev/null
@@ -1,30 +0,0 @@
-/**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of this source tree. An additional grant
- * of patent rights can be found in the PATENTS file in the same directory.
- *
- * @flow
- */
-'use strict';
-
-// Based on the React repo.
-
-module.exports = {
-  ASYNC_MODE_NUMBER: 0xeacf,
-  ASYNC_MODE_SYMBOL_STRING: 'Symbol(react.async_mode)',
-  CONTEXT_CONSUMER_NUMBER: 0xeace,
-  CONTEXT_CONSUMER_SYMBOL_STRING: 'Symbol(react.context)',
-  CONTEXT_PROVIDER_NUMBER: 0xeacd,
-  CONTEXT_PROVIDER_SYMBOL_STRING: 'Symbol(react.provider)',
-  FORWARD_REF_NUMBER: 0xead0,
-  FORWARD_REF_SYMBOL_STRING: 'Symbol(react.forward_ref)',
-  PROFILER_NUMBER: 0xead2,
-  PROFILER_SYMBOL_STRING: 'Symbol(react.profiler)',
-  STRICT_MODE_NUMBER: 0xeacc,
-  STRICT_MODE_SYMBOL_STRING: 'Symbol(react.strict_mode)',
-  PLACEHOLDER_NUMBER: 0xead1,
-  PLACEHOLDER_SYMBOL_STRING: 'Symbol(react.placeholder)',
-};
diff --git a/backend/ReactTypeOfWork.js b/backend/ReactTypeOfWork.js
deleted file mode 100644
index 90f488f3c0..0000000000
--- a/backend/ReactTypeOfWork.js
+++ /dev/null
@@ -1,33 +0,0 @@
-/**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of this source tree. An additional grant
- * of patent rights can be found in the PATENTS file in the same directory.
- *
- * @flow
- */
-'use strict';
-
-// Copied from React repo.
-
-module.exports = {
-  IndeterminateComponent: 0, // Before we know whether it is functional or class
-  FunctionalComponent: 1,
-  ClassComponent: 2,
-  HostRoot: 3, // Root of a host tree. Could be nested inside another node.
-  HostPortal: 4, // A subtree. Could be an entry point to a different renderer.
-  HostComponent: 5,
-  HostText: 6,
-  CoroutineComponent: 7,
-  CoroutineHandlerPhase: 8,
-  YieldComponent: 9,
-  Fragment: 10,
-  Mode: 11,
-  ContextConsumer: 12,
-  ContextProvider: 13,
-  ForwardRef: 14,
-  Profiler: 15,
-  Placeholder: 16,
-};
diff --git a/backend/attachRendererFiber.js b/backend/attachRendererFiber.js
index 2f7a311fd5..02b6ce3c86 100644
--- a/backend/attachRendererFiber.js
+++ b/backend/attachRendererFiber.js
@@ -10,19 +10,355 @@
  */
 'use strict';
 
-import type {Hook, ReactRenderer, Helpers} from './types';
-var getDataFiber = require('./getDataFiber');
-var {
-  ClassComponent,
-  FunctionalComponent,
-  ContextConsumer,
-  HostRoot,
-} = require('./ReactTypeOfWork');
-
-// Inlined from ReactTypeOfSideEffect
-var PerformedWork = 1;
+import type {Hook, ReactRenderer, DataType, Helpers} from './types';
+
+var semver = require('semver');
+
+var copyWithSet = require('./copyWithSet');
+var getDisplayName = require('./getDisplayName');
+
+function getInternalReactConstants(version) {
+  var ReactTypeOfWork;
+  var ReactSymbols;
+  var ReactTypeOfSideEffect;
+
+  // **********************************************************
+  // The section below is copy-pasted from files in React repo.
+  // Keep it in sync, and add version guards if it changes.
+  // **********************************************************
+  if (semver.gte(version, '16.4.3')) {
+    ReactTypeOfWork = {
+      IndeterminateComponent: 0,
+      FunctionalComponent: 1,
+      FunctionalComponentLazy: 2,
+      ClassComponent: 3,
+      ClassComponentLazy: 4,
+      HostRoot: 5,
+      HostPortal: 6,
+      HostComponent: 7,
+      HostText: 8,
+      Fragment: 9,
+      Mode: 10,
+      ContextConsumer: 11,
+      ContextProvider: 12,
+      ForwardRef: 13,
+      ForwardRefLazy: 14,
+      Profiler: 15,
+      PlaceholderComponent: 16,
+    };
+  } else {
+    ReactTypeOfWork = {
+      IndeterminateComponent: 0,
+      FunctionalComponent: 1,
+      ClassComponent: 2,
+      HostRoot: 3,
+      HostPortal: 4,
+      HostComponent: 5,
+      HostText: 6,
+      CoroutineComponent: 7,
+      CoroutineHandlerPhase: 8,
+      YieldComponent: 9,
+      Fragment: 10,
+      Mode: 11,
+      ContextConsumer: 12,
+      ContextProvider: 13,
+      ForwardRef: 14,
+      Profiler: 15,
+      Placeholder: 16,
+    };
+  }
+  ReactSymbols = {
+    ASYNC_MODE_NUMBER: 0xeacf,
+    ASYNC_MODE_SYMBOL_STRING: 'Symbol(react.async_mode)',
+    CONTEXT_CONSUMER_NUMBER: 0xeace,
+    CONTEXT_CONSUMER_SYMBOL_STRING: 'Symbol(react.context)',
+    CONTEXT_PROVIDER_NUMBER: 0xeacd,
+    CONTEXT_PROVIDER_SYMBOL_STRING: 'Symbol(react.provider)',
+    FORWARD_REF_NUMBER: 0xead0,
+    FORWARD_REF_SYMBOL_STRING: 'Symbol(react.forward_ref)',
+    PROFILER_NUMBER: 0xead2,
+    PROFILER_SYMBOL_STRING: 'Symbol(react.profiler)',
+    STRICT_MODE_NUMBER: 0xeacc,
+    STRICT_MODE_SYMBOL_STRING: 'Symbol(react.strict_mode)',
+    PLACEHOLDER_NUMBER: 0xead1,
+    PLACEHOLDER_SYMBOL_STRING: 'Symbol(react.placeholder)',
+  };
+  ReactTypeOfSideEffect = {
+    PerformedWork: 1,
+  };
+  // **********************************************************
+  // End of copy paste.
+  // **********************************************************
+  return {
+    ReactTypeOfWork,
+    ReactSymbols,
+    ReactTypeOfSideEffect,
+  };
+}
 
 function attachRendererFiber(hook: Hook, rid: string, renderer: ReactRenderer): Helpers {
+  var {ReactTypeOfWork, ReactSymbols, ReactTypeOfSideEffect} = getInternalReactConstants(renderer.version);
+  var {PerformedWork} = ReactTypeOfSideEffect;
+  var {
+    FunctionalComponent,
+    ClassComponent,
+    ContextConsumer,
+    HostRoot,
+    HostPortal,
+    HostComponent,
+    HostText,
+    Fragment,
+  } = ReactTypeOfWork;
+  var {
+    ASYNC_MODE_NUMBER,
+    ASYNC_MODE_SYMBOL_STRING,
+    CONTEXT_CONSUMER_NUMBER,
+    CONTEXT_CONSUMER_SYMBOL_STRING,
+    CONTEXT_PROVIDER_NUMBER,
+    CONTEXT_PROVIDER_SYMBOL_STRING,
+    FORWARD_REF_NUMBER,
+    FORWARD_REF_SYMBOL_STRING,
+    PROFILER_NUMBER,
+    PROFILER_SYMBOL_STRING,
+    STRICT_MODE_NUMBER,
+    STRICT_MODE_SYMBOL_STRING,
+    PLACEHOLDER_NUMBER,
+    PLACEHOLDER_SYMBOL_STRING,
+  } = ReactSymbols;
+
+  // TODO: we might want to change the data structure
+  // once we no longer suppport Stack versions of `getData`.
+  function getDataFiber(fiber: Object): DataType {
+    var type = fiber.type;
+    var key = fiber.key;
+    var ref = fiber.ref;
+    var source = fiber._debugSource;
+    var publicInstance = null;
+    var props = null;
+    var state = null;
+    var children = null;
+    var context = null;
+    var updater = null;
+    var nodeType = null;
+    var name = null;
+    var text = null;
+
+    // Profiler data
+    var actualDuration = null;
+    var actualStartTime = null;
+    var treeBaseDuration = null;
+
+    switch (fiber.tag) {
+      case FunctionalComponent:
+      case ClassComponent:
+        nodeType = 'Composite';
+        name = getDisplayName(fiber.type);
+        publicInstance = fiber.stateNode;
+        props = fiber.memoizedProps;
+        state = fiber.memoizedState;
+        if (publicInstance != null) {
+          context = publicInstance.context;
+          if (context && Object.keys(context).length === 0) {
+            context = null;
+          }
+        }
+        const inst = publicInstance;
+        if (inst) {
+          updater = {
+            setState: inst.setState && inst.setState.bind(inst),
+            forceUpdate: inst.forceUpdate && inst.forceUpdate.bind(inst),
+            setInProps: inst.forceUpdate && setInProps.bind(null, fiber),
+            setInState: inst.forceUpdate && setInState.bind(null, inst),
+            setInContext: inst.forceUpdate && setInContext.bind(null, inst),
+          };
+        }
+        children = [];
+        break;
+      case HostRoot:
+        nodeType = 'Wrapper';
+        children = [];
+        break;
+      case HostPortal:
+        nodeType = 'Portal';
+        name = 'ReactPortal';
+        props = {
+          target: fiber.stateNode.containerInfo,
+        };
+        children = [];
+        break;
+      case HostComponent:
+        nodeType = 'Native';
+        name = fiber.type;
+
+        // TODO (bvaughn) we plan to remove this prefix anyway.
+        // We can cut this special case out when it's gone.
+        name = name.replace('topsecret-', '');
+
+        publicInstance = fiber.stateNode;
+        props = fiber.memoizedProps;
+        if (
+          typeof props.children === 'string' ||
+          typeof props.children === 'number'
+        ) {
+          children = props.children.toString();
+        } else {
+          children = [];
+        }
+        if (typeof fiber.stateNode.setNativeProps === 'function') {
+          // For editing styles in RN
+          updater = {
+            setNativeProps(nativeProps) {
+              fiber.stateNode.setNativeProps(nativeProps);
+            },
+          };
+        }
+        break;
+      case HostText:
+        nodeType = 'Text';
+        text = fiber.memoizedProps;
+        break;
+      case Fragment:
+        nodeType = 'Wrapper';
+        children = [];
+        break;
+      default: // Coroutines and yields
+        const symbolOrNumber = typeof type === 'object' && type !== null
+          ? type.$$typeof
+          : type;
+        // $FlowFixMe facebook/flow/issues/2362
+        const switchValue = typeof symbolOrNumber === 'symbol'
+          ? symbolOrNumber.toString()
+          : symbolOrNumber;
+
+        switch (switchValue) {
+          case ASYNC_MODE_NUMBER:
+          case ASYNC_MODE_SYMBOL_STRING:
+            nodeType = 'Special';
+            name = 'AsyncMode';
+            children = [];
+            break;
+          case CONTEXT_PROVIDER_NUMBER:
+          case CONTEXT_PROVIDER_SYMBOL_STRING:
+            nodeType = 'Special';
+            props = fiber.memoizedProps;
+            name = 'Context.Provider';
+            children = [];
+            break;
+          case CONTEXT_CONSUMER_NUMBER:
+          case CONTEXT_CONSUMER_SYMBOL_STRING:
+            nodeType = 'Special';
+            props = fiber.memoizedProps;
+            // TODO: TraceUpdatesBackendManager currently depends on this.
+            // If you change .name, figure out a more resilient way to detect it.
+            name = 'Context.Consumer';
+            children = [];
+            break;
+          case STRICT_MODE_NUMBER:
+          case STRICT_MODE_SYMBOL_STRING:
+            nodeType = 'Special';
+            name = 'StrictMode';
+            children = [];
+            break;
+          case FORWARD_REF_NUMBER:
+          case FORWARD_REF_SYMBOL_STRING:
+            const functionName = getDisplayName(fiber.type.render, '');
+            nodeType = 'Special';
+            name = functionName !== '' ? `ForwardRef(${functionName})` : 'ForwardRef';
+            children = [];
+            break;
+          case PLACEHOLDER_NUMBER:
+          case PLACEHOLDER_SYMBOL_STRING:
+            nodeType = 'Special';
+            name = 'Placeholder';
+            props = fiber.memoizedProps;
+            children = [];
+            break;
+          case PROFILER_NUMBER:
+          case PROFILER_SYMBOL_STRING:
+            nodeType = 'Special';
+            props = fiber.memoizedProps;
+            name = `Profiler(${fiber.memoizedProps.id})`;
+            children = [];
+            break;
+          default:
+            nodeType = 'Native';
+            props = fiber.memoizedProps;
+            name = 'TODO_NOT_IMPLEMENTED_YET';
+            children = [];
+            break;
+        }
+        break;
+    }
+
+    if (Array.isArray(children)) {
+      let child = fiber.child;
+      while (child) {
+        children.push(getOpaqueNode(child));
+        child = child.sibling;
+      }
+    }
+
+    if (fiber.actualDuration !== undefined) {
+      actualDuration = fiber.actualDuration;
+      actualStartTime = fiber.actualStartTime;
+      treeBaseDuration = fiber.treeBaseDuration;
+    }
+
+    // $FlowFixMe
+    return {
+      nodeType,
+      type,
+      key,
+      ref,
+      source,
+      name,
+      props,
+      state,
+      context,
+      children,
+      text,
+      updater,
+      publicInstance,
+
+      // Profiler data
+      actualDuration,
+      actualStartTime,
+      treeBaseDuration,
+    };
+  }
+
+  function setInProps(fiber, path: Array<string | number>, value: any) {
+    const inst = fiber.stateNode;
+    fiber.pendingProps = copyWithSet(inst.props, path, value);
+    if (fiber.alternate) {
+      // We don't know which fiber is the current one because DevTools may bail out of getDataFiber() call,
+      // and so the data object may refer to another version of the fiber. Therefore we update pendingProps
+      // on both. I hope that this is safe.
+      fiber.alternate.pendingProps = fiber.pendingProps;
+    }
+    fiber.stateNode.forceUpdate();
+  }
+
+  function setInState(inst, path: Array<string | number>, value: any) {
+    setIn(inst.state, path, value);
+    inst.forceUpdate();
+  }
+
+  function setInContext(inst, path: Array<string | number>, value: any) {
+    setIn(inst.context, path, value);
+    inst.forceUpdate();
+  }
+
+  function setIn(obj: Object, path: Array<string | number>, value: any) {
+    var last = path.pop();
+    var parent = path.reduce((obj_, attr) => obj_ ? obj_[attr] : null, obj);
+    if (parent) {
+      parent[last] = value;
+    }
+  }
+
+
+
   // This is a slightly annoying indirection.
   // It is currently necessary because DevTools wants
   // to use unique objects as keys for instances.
@@ -90,7 +426,7 @@ function attachRendererFiber(hook: Hook, rid: string, renderer: ReactRenderer):
   function enqueueMount(fiber) {
     pendingEvents.push({
       internalInstance: getOpaqueNode(fiber),
-      data: getDataFiber(fiber, getOpaqueNode),
+      data: getDataFiber(fiber),
       renderer: rid,
       type: 'mount',
     });
@@ -117,7 +453,7 @@ function attachRendererFiber(hook: Hook, rid: string, renderer: ReactRenderer):
       if (haveProfilerTimesChanged(fiber.alternate, fiber)) {
         pendingEvents.push({
           internalInstance: getOpaqueNode(fiber),
-          data: getDataFiber(fiber, getOpaqueNode),
+          data: getDataFiber(fiber),
           renderer: rid,
           type: 'updateProfileTimes',
         });
@@ -126,7 +462,7 @@ function attachRendererFiber(hook: Hook, rid: string, renderer: ReactRenderer):
     }
     pendingEvents.push({
       internalInstance: getOpaqueNode(fiber),
-      data: getDataFiber(fiber, getOpaqueNode),
+      data: getDataFiber(fiber),
       renderer: rid,
       type: 'update',
     });
diff --git a/backend/getData.js b/backend/getData.js
index 6356ce746f..cccb4fa1e4 100644
--- a/backend/getData.js
+++ b/backend/getData.js
@@ -10,6 +10,11 @@
  */
 'use strict';
 
+// ----------------------------------------------------
+// This is Stack-only version.
+// The Fiber version is inlined in attachRendererFiber.
+// ----------------------------------------------------
+
 import type {DataType} from './types';
 var copyWithSet = require('./copyWithSet');
 var getDisplayName = require('./getDisplayName');
diff --git a/backend/getData012.js b/backend/getData012.js
index 577b26b3fb..d5a329f748 100644
--- a/backend/getData012.js
+++ b/backend/getData012.js
@@ -10,6 +10,11 @@
  */
 'use strict';
 
+// ----------------------------------------------------
+// This is Stack-only version.
+// The Fiber version is inlined in attachRendererFiber.
+// ----------------------------------------------------
+
 import type {DataType} from './types';
 var copyWithSet = require('./copyWithSet');
 
diff --git a/backend/getDataFiber.js b/backend/getDataFiber.js
deleted file mode 100644
index 9856e2c31f..0000000000
--- a/backend/getDataFiber.js
+++ /dev/null
@@ -1,273 +0,0 @@
-/**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of this source tree. An additional grant
- * of patent rights can be found in the PATENTS file in the same directory.
- *
- * @flow
- */
-'use strict';
-
-import type {DataType} from './types';
-var copyWithSet = require('./copyWithSet');
-var getDisplayName = require('./getDisplayName');
-var {
-  FunctionalComponent,
-  ClassComponent,
-  HostRoot,
-  HostPortal,
-  HostComponent,
-  HostText,
-  Fragment,
-} = require('./ReactTypeOfWork');
-var {
-  ASYNC_MODE_NUMBER,
-  ASYNC_MODE_SYMBOL_STRING,
-  CONTEXT_CONSUMER_NUMBER,
-  CONTEXT_CONSUMER_SYMBOL_STRING,
-  CONTEXT_PROVIDER_NUMBER,
-  CONTEXT_PROVIDER_SYMBOL_STRING,
-  FORWARD_REF_NUMBER,
-  FORWARD_REF_SYMBOL_STRING,
-  PROFILER_NUMBER,
-  PROFILER_SYMBOL_STRING,
-  STRICT_MODE_NUMBER,
-  STRICT_MODE_SYMBOL_STRING,
-  PLACEHOLDER_NUMBER,
-  PLACEHOLDER_SYMBOL_STRING,
-} = require('./ReactSymbols');
-
-// TODO: we might want to change the data structure
-// once we no longer suppport Stack versions of `getData`.
-function getDataFiber(fiber: Object, getOpaqueNode: (fiber: Object) => Object): DataType {
-  var type = fiber.type;
-  var key = fiber.key;
-  var ref = fiber.ref;
-  var source = fiber._debugSource;
-  var publicInstance = null;
-  var props = null;
-  var state = null;
-  var children = null;
-  var context = null;
-  var updater = null;
-  var nodeType = null;
-  var name = null;
-  var text = null;
-
-  // Profiler data
-  var actualDuration = null;
-  var actualStartTime = null;
-  var treeBaseDuration = null;
-
-  switch (fiber.tag) {
-    case FunctionalComponent:
-    case ClassComponent:
-      nodeType = 'Composite';
-      name = getDisplayName(fiber.type);
-      publicInstance = fiber.stateNode;
-      props = fiber.memoizedProps;
-      state = fiber.memoizedState;
-      if (publicInstance != null) {
-        context = publicInstance.context;
-        if (context && Object.keys(context).length === 0) {
-          context = null;
-        }
-      }
-      const inst = publicInstance;
-      if (inst) {
-        updater = {
-          setState: inst.setState && inst.setState.bind(inst),
-          forceUpdate: inst.forceUpdate && inst.forceUpdate.bind(inst),
-          setInProps: inst.forceUpdate && setInProps.bind(null, fiber),
-          setInState: inst.forceUpdate && setInState.bind(null, inst),
-          setInContext: inst.forceUpdate && setInContext.bind(null, inst),
-        };
-      }
-      children = [];
-      break;
-    case HostRoot:
-      nodeType = 'Wrapper';
-      children = [];
-      break;
-    case HostPortal:
-      nodeType = 'Portal';
-      name = 'ReactPortal';
-      props = {
-        target: fiber.stateNode.containerInfo,
-      };
-      children = [];
-      break;
-    case HostComponent:
-      nodeType = 'Native';
-      name = fiber.type;
-
-      // TODO (bvaughn) we plan to remove this prefix anyway.
-      // We can cut this special case out when it's gone.
-      name = name.replace('topsecret-', '');
-
-      publicInstance = fiber.stateNode;
-      props = fiber.memoizedProps;
-      if (
-        typeof props.children === 'string' ||
-        typeof props.children === 'number'
-      ) {
-        children = props.children.toString();
-      } else {
-        children = [];
-      }
-      if (typeof fiber.stateNode.setNativeProps === 'function') {
-        // For editing styles in RN
-        updater = {
-          setNativeProps(nativeProps) {
-            fiber.stateNode.setNativeProps(nativeProps);
-          },
-        };
-      }
-      break;
-    case HostText:
-      nodeType = 'Text';
-      text = fiber.memoizedProps;
-      break;
-    case Fragment:
-      nodeType = 'Wrapper';
-      children = [];
-      break;
-    default: // Coroutines and yields
-      const symbolOrNumber = typeof type === 'object' && type !== null
-        ? type.$$typeof
-        : type;
-      // $FlowFixMe facebook/flow/issues/2362
-      const switchValue = typeof symbolOrNumber === 'symbol'
-        ? symbolOrNumber.toString()
-        : symbolOrNumber;
-
-      switch (switchValue) {
-        case ASYNC_MODE_NUMBER:
-        case ASYNC_MODE_SYMBOL_STRING:
-          nodeType = 'Special';
-          name = 'AsyncMode';
-          children = [];
-          break;
-        case CONTEXT_PROVIDER_NUMBER:
-        case CONTEXT_PROVIDER_SYMBOL_STRING:
-          nodeType = 'Special';
-          props = fiber.memoizedProps;
-          name = 'Context.Provider';
-          children = [];
-          break;
-        case CONTEXT_CONSUMER_NUMBER:
-        case CONTEXT_CONSUMER_SYMBOL_STRING:
-          nodeType = 'Special';
-          props = fiber.memoizedProps;
-          // TODO: TraceUpdatesBackendManager currently depends on this.
-          // If you change .name, figure out a more resilient way to detect it.
-          name = 'Context.Consumer';
-          children = [];
-          break;
-        case STRICT_MODE_NUMBER:
-        case STRICT_MODE_SYMBOL_STRING:
-          nodeType = 'Special';
-          name = 'StrictMode';
-          children = [];
-          break;
-        case FORWARD_REF_NUMBER:
-        case FORWARD_REF_SYMBOL_STRING:
-          const functionName = getDisplayName(fiber.type.render, '');
-          nodeType = 'Special';
-          name = functionName !== '' ? `ForwardRef(${functionName})` : 'ForwardRef';
-          children = [];
-          break;
-        case PLACEHOLDER_NUMBER:
-        case PLACEHOLDER_SYMBOL_STRING:
-          nodeType = 'Special';
-          name = 'Placeholder';
-          props = fiber.memoizedProps;
-          children = [];
-          break;
-        case PROFILER_NUMBER:
-        case PROFILER_SYMBOL_STRING:
-          nodeType = 'Special';
-          props = fiber.memoizedProps;
-          name = `Profiler(${fiber.memoizedProps.id})`;
-          children = [];
-          break;
-        default:
-          nodeType = 'Native';
-          props = fiber.memoizedProps;
-          name = 'TODO_NOT_IMPLEMENTED_YET';
-          children = [];
-          break;
-      }
-      break;
-  }
-
-  if (Array.isArray(children)) {
-    let child = fiber.child;
-    while (child) {
-      children.push(getOpaqueNode(child));
-      child = child.sibling;
-    }
-  }
-
-  if (fiber.actualDuration !== undefined) {
-    actualDuration = fiber.actualDuration;
-    actualStartTime = fiber.actualStartTime;
-    treeBaseDuration = fiber.treeBaseDuration;
-  }
-
-  // $FlowFixMe
-  return {
-    nodeType,
-    type,
-    key,
-    ref,
-    source,
-    name,
-    props,
-    state,
-    context,
-    children,
-    text,
-    updater,
-    publicInstance,
-
-    // Profiler data
-    actualDuration,
-    actualStartTime,
-    treeBaseDuration,
-  };
-}
-
-function setInProps(fiber, path: Array<string | number>, value: any) {
-  const inst = fiber.stateNode;
-  fiber.pendingProps = copyWithSet(inst.props, path, value);
-  if (fiber.alternate) {
-    // We don't know which fiber is the current one because DevTools may bail out of getDataFiber() call,
-    // and so the data object may refer to another version of the fiber. Therefore we update pendingProps
-    // on both. I hope that this is safe.
-    fiber.alternate.pendingProps = fiber.pendingProps;
-  }
-  fiber.stateNode.forceUpdate();
-}
-
-function setInState(inst, path: Array<string | number>, value: any) {
-  setIn(inst.state, path, value);
-  inst.forceUpdate();
-}
-
-function setInContext(inst, path: Array<string | number>, value: any) {
-  setIn(inst.context, path, value);
-  inst.forceUpdate();
-}
-
-function setIn(obj: Object, path: Array<string | number>, value: any) {
-  var last = path.pop();
-  var parent = path.reduce((obj_, attr) => obj_ ? obj_[attr] : null, obj);
-  if (parent) {
-    parent[last] = value;
-  }
-}
-
-module.exports = getDataFiber;
diff --git a/package.json b/package.json
index 5fd3e916fe..9b74be359f 100644
--- a/package.json
+++ b/package.json
@@ -36,6 +36,7 @@
     "react-portal": "^3.1.0",
     "react-virtualized-auto-sizer": "^1.0.2",
     "react-window": "^1.1.1",
+    "semver": "^5.5.1",
     "webpack": "1.12.9"
   },
   "license": "BSD-3-Clause",
diff --git a/yarn.lock b/yarn.lock
index 12e7358542..c591900478 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -6186,6 +6186,10 @@ semver@^5.0.1, semver@^5.4.1:
   version "5.5.0"
   resolved "https://registry.yarnpkg.com/semver/-/semver-5.5.0.tgz#dc4bbc7a6ca9d916dee5d43516f0092b58f7b8ab"
 
+semver@^5.5.1:
+  version "5.5.1"
+  resolved "https://registry.yarnpkg.com/semver/-/semver-5.5.1.tgz#7dfdd8814bdb7cabc7be0fb1d734cfb66c940477"
+
 set-blocking@^2.0.0, set-blocking@~2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/set-blocking/-/set-blocking-2.0.0.tgz#045f9782d011ae9a6803ddd382b24392b3d890f7"