Framework: Upgrade React version.

element/index.js

@@ -1,7 +1,7 @@
 /**
  * External dependencies
  */
-import { createElement, Component, cloneElement, Children, Fragment } from 'react';
+import { createContext, createElement, Component, cloneElement, Children, Fragment } from 'react';
 import { render, findDOMNode, createPortal, unmountComponentAtNode } from 'react-dom';
 import { renderToStaticMarkup } from 'react-dom/server';
 import {
@@ -71,6 +71,15 @@ export { Children };
  */
 export { Fragment };
 
+/**
+ * Creates a context object containing two components: a provider and consumer.
+ *
+ * @param {object} defaultValue Data stored in the context.
+ *
+ * @return {Object} Context object.
+ */
+export { createContext };
+
 /**
  * Creates a portal into which a component can be rendered.
  *

lib/client-assets.php

@@ -345,16 +345,16 @@ function gutenberg_register_vendor_scripts() {
 
 	gutenberg_register_vendor_script(
 		'react',
-		'https://unpkg.com/react@16.2.0/umd/react' . $react_suffix . '.js'
+		'https://unpkg.com/react@16.3.0-alpha.1/umd/react' . $react_suffix . '.js'
 	);
 	gutenberg_register_vendor_script(
 		'react-dom',
-		'https://unpkg.com/react-dom@16.2.0/umd/react-dom' . $react_suffix . '.js',
+		'https://unpkg.com/react-dom@16.3.0-alpha.1/umd/react-dom' . $react_suffix . '.js',
 		array( 'react' )
 	);
 	gutenberg_register_vendor_script(
 		'react-dom-server',
-		'https://unpkg.com/react-dom@16.2.0/umd/react-dom-server.browser' . $react_suffix . '.js',
+		'https://unpkg.com/react-dom@16.3.0-alpha.1/umd/react-dom-server.browser' . $react_suffix . '.js',
 		array( 'react' )
 	);
 	$moment_script = SCRIPT_DEBUG ? 'moment.js' : 'min/moment.min.js';

package.json

@@ -39,12 +39,12 @@
 		"prop-types": "15.5.10",
 		"querystringify": "1.0.0",
 		"re-resizable": "4.0.3",
-		"react": "16.2.0",
+		"react": "16.3.0-alpha.1",
 		"react-autosize-textarea": "2.0.0",
 		"react-click-outside": "2.3.1",
 		"react-color": "2.13.4",
 		"react-datepicker": "0.61.0",
-		"react-dom": "16.2.0",
+		"react-dom": "16.3.0-alpha.1",
 		"react-redux": "5.0.6",
 		"redux": "3.7.2",
 		"redux-multi": "0.1.12",