diff --git a/client/auth/test/login.jsx b/client/auth/test/login.jsx
index dae235614f580..21fde5c49dcc6 100644
--- a/client/auth/test/login.jsx
+++ b/client/auth/test/login.jsx
@@ -12,7 +12,7 @@ import useFakeDom from 'test/helpers/use-fake-dom';
 import useMockery from 'test/helpers/use-mockery';
 
 describe( 'LoginTest', function() {
-	let Login, loginStub, page, React, ReactDom, ReactInjection, TestUtils;
+	let Login, loginStub, page, React, ReactDom, ReactClass, TestUtils;
 
 	useFakeDom.withContainer();
 	useMockery( ( mockery ) => {
@@ -26,9 +26,9 @@ describe( 'LoginTest', function() {
 	before( () => {
 		React = require( 'react' );
 		ReactDom = require( 'react-dom' );
-		ReactInjection = require( 'react/lib/ReactInjection' );
+		ReactClass = require( 'react/lib/ReactClass' );
 		TestUtils = require( 'react-addons-test-utils' );
-		ReactInjection.Class.injectMixin( { translate: identity } );
+		ReactClass.injection.injectMixin( { translate: identity } );
 		Login = require( '../login.jsx' );
 		page = ReactDom.render( <Login />, useFakeDom.getContainer() );
 	} );
diff --git a/client/boot/index.js b/client/boot/index.js
index 553db3ed6ac4e..42ca408bb8c23 100644
--- a/client/boot/index.js
+++ b/client/boot/index.js
@@ -10,7 +10,7 @@ if ( process.env.NODE_ENV === 'development' ) {
 var React = require( 'react' ),
 	ReactDom = require( 'react-dom' ),
 	store = require( 'store' ),
-	ReactInjection = require( 'react/lib/ReactInjection' ),
+	ReactClass = require( 'react/lib/ReactClass' ),
 	some = require( 'lodash/some' ),
 	startsWith = require( 'lodash/startsWith' ),
 	debug = require( 'debug' )( 'calypso' ),
@@ -70,7 +70,7 @@ function init() {
 		i18n.setLocale( i18nLocaleStringsObject );
 	}
 
-	ReactInjection.Class.injectMixin( i18n.mixin );
+	ReactClass.injection.injectMixin( i18n.mixin );
 
 	// Infer touch screen by checking if device supports touch events
 	// See touch-detect/README.md
@@ -130,7 +130,7 @@ function loadDevModulesAndBoot() {
 		// Since loading this fragment is asynchronous and we need to inject this mixin into all React classes,
 		// we have to wait for it to load before proceeding with the application's startup.
 		require.ensure( [], function() {
-			ReactInjection.Class.injectMixin( require( 'lib/mixins/render-visualizer' ) );
+			ReactClass.injection.injectMixin( require( 'lib/mixins/render-visualizer' ) );
 			boot();
 		}, 'devmodules' );
 
diff --git a/client/components/count/test/index.jsx b/client/components/count/test/index.jsx
index 423e2e5dc414b..7fc84e45aaa9d 100644
--- a/client/components/count/test/index.jsx
+++ b/client/components/count/test/index.jsx
@@ -5,17 +5,17 @@ var expect = require( 'chai' ).expect,
 	useMockery = require( 'test/helpers/use-mockery' );
 
 describe( 'Count', function() {
-	var React, ReactInjection, TestUtils, Count, renderer;
+	var React, ReactClass, TestUtils, Count, renderer;
 
 	// really only using Mockery for the clean module cache
 	useMockery();
 
 	before( function() {
 		React = require( 'react' );
-		ReactInjection = require( 'react/lib/ReactInjection' );
+		ReactClass = require( 'react/lib/ReactClass' );
 		TestUtils = require( 'react-addons-test-utils' );
 
-		ReactInjection.Class.injectMixin( require( 'i18n-calypso' ).mixin );
+		ReactClass.injection.injectMixin( require( 'i18n-calypso' ).mixin );
 		Count = require( '../' );
 	} );
 
diff --git a/client/components/forms/counted-textarea/test/index.jsx b/client/components/forms/counted-textarea/test/index.jsx
index db75f8893db81..9dd8d2c2900b3 100644
--- a/client/components/forms/counted-textarea/test/index.jsx
+++ b/client/components/forms/counted-textarea/test/index.jsx
@@ -2,7 +2,7 @@
  * External dependencies
  */
 var React = require( 'react' ),
-	ReactInjection = require( 'react/lib/ReactInjection' ),
+	ReactClass = require( 'react/lib/ReactClass' ),
 	TestUtils = require( 'react-addons-test-utils' ),
 	expect = require( 'chai' ).expect,
 	i18n = require( 'i18n-calypso' );
@@ -11,7 +11,7 @@ describe( 'index', function() {
 	var CountedTextarea, renderer;
 
 	before( function() {
-		ReactInjection.Class.injectMixin( i18n.mixin );
+		ReactClass.injection.injectMixin( i18n.mixin );
 		CountedTextarea = require( '../' );
 	} );
 
diff --git a/client/components/forms/form-phone-input/test/index.jsx b/client/components/forms/form-phone-input/test/index.jsx
index e2cfd8b98d22e..04802d66348fd 100644
--- a/client/components/forms/form-phone-input/test/index.jsx
+++ b/client/components/forms/form-phone-input/test/index.jsx
@@ -7,7 +7,7 @@ var expect = require( 'chai' ).expect,
 	useMockery = require( 'test/helpers/use-mockery' );
 
 describe( 'FormPhoneInput', function() {
-	var React, ReactDom, ReactInjection, TestUtils, i18n, mockCountriesList, mockCountriesListEmpty, FormPhoneInput, countries, container;
+	var React, ReactDom, ReactClass, TestUtils, i18n, mockCountriesList, mockCountriesListEmpty, FormPhoneInput, countries, container;
 
 	useFakeDom();
 	useMockery();
@@ -15,7 +15,7 @@ describe( 'FormPhoneInput', function() {
 	before( function() {
 		ReactDom = require( 'react-dom' );
 		React = require( 'react' );
-		ReactInjection = require( 'react/lib/ReactInjection' );
+		ReactClass = require( 'react/lib/ReactClass' );
 		TestUtils = require( 'react-addons-test-utils' );
 
 		i18n = require( 'i18n-calypso' );
@@ -24,7 +24,7 @@ describe( 'FormPhoneInput', function() {
 
 		countries = mockCountriesList.get();
 
-		ReactInjection.Class.injectMixin( i18n.mixin );
+		ReactClass.injection.injectMixin( i18n.mixin );
 		FormPhoneInput = require( 'components/forms/form-phone-input' );
 		container = getContainer();
 	} );
diff --git a/client/my-sites/plugins/plugins-list/test/index.jsx b/client/my-sites/plugins/plugins-list/test/index.jsx
index 2816c208d8977..77db81512c711 100644
--- a/client/my-sites/plugins/plugins-list/test/index.jsx
+++ b/client/my-sites/plugins/plugins-list/test/index.jsx
@@ -34,9 +34,9 @@ describe( 'PluginsList', () => {
 	before( () => {
 		React = require( 'react' );
 		TestUtils = require( 'react-addons-test-utils' );
-		const ReactInjection = require( 'react/lib/ReactInjection' );
+		const ReactClass = require( 'react/lib/ReactClass' );
 
-		ReactInjection.Class.injectMixin( require( 'i18n-calypso' ).mixin );
+		ReactClass.injection.injectMixin( require( 'i18n-calypso' ).mixin );
 
 		testRenderer = TestUtils.renderIntoDocument;
 
diff --git a/client/my-sites/upgrades/domain-management/edit/test/mapped-domain.js b/client/my-sites/upgrades/domain-management/edit/test/mapped-domain.js
index 0ef770deb7485..ac0b06481a8ae 100644
--- a/client/my-sites/upgrades/domain-management/edit/test/mapped-domain.js
+++ b/client/my-sites/upgrades/domain-management/edit/test/mapped-domain.js
@@ -39,8 +39,8 @@ describe( 'mapped-domain', () => {
 		React = require( 'react' );
 		TestUtils = require( 'react-addons-test-utils' );
 
-		const ReactInjection = require( 'react/lib/ReactInjection' );
-		ReactInjection.Class.injectMixin( require( 'i18n-calypso' ).mixin );
+		const ReactClass = require( 'react/lib/ReactClass' );
+		ReactClass.injection.injectMixin( require( 'i18n-calypso' ).mixin );
 		MappedDomain = require( '../mapped-domain.jsx' );
 	} );
 
diff --git a/client/my-sites/upgrades/domain-management/list/test/index.js b/client/my-sites/upgrades/domain-management/list/test/index.js
index 382392ab81e47..6ce4e78e11d4e 100644
--- a/client/my-sites/upgrades/domain-management/list/test/index.js
+++ b/client/my-sites/upgrades/domain-management/list/test/index.js
@@ -16,7 +16,7 @@ import { useSandbox } from 'test/helpers/use-sinon';
 describe( 'index', function() {
 	let React,
 		ReactDom,
-		ReactInjection,
+		ReactClass,
 		DomainList,
 		TestUtils,
 		noticeTypes,
@@ -52,8 +52,8 @@ describe( 'index', function() {
 
 		noticeTypes = require( '../constants' );
 
-		ReactInjection = require( 'react/lib/ReactInjection' );
-		ReactInjection.Class.injectMixin( require( 'i18n-calypso' ).mixin );
+		ReactClass = require( 'react/lib/ReactClass' );
+		ReactClass.injection.injectMixin( require( 'i18n-calypso' ).mixin );
 
 		DomainList = require( '../' ).List;
 	} );