diff --git a/package.json b/package.json
index e8c9842c4b7..754ed41a54b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "private": true,
-  "version": "16.4.1",
+  "version": "16.4.3-alpha.0",
   "workspaces": [
     "packages/*"
   ],
diff --git a/packages/create-subscription/package.json b/packages/create-subscription/package.json
index ccfcb5dfe82..6fc16864137 100644
--- a/packages/create-subscription/package.json
+++ b/packages/create-subscription/package.json
@@ -1,7 +1,7 @@
 {
   "name": "create-subscription",
   "description": "utility for subscribing to external data sources inside React components",
-  "version": "16.4.1",
+  "version": "16.4.3-alpha.0",
   "repository": "facebook/react",
   "files": [
     "LICENSE",
diff --git a/packages/react-art/package.json b/packages/react-art/package.json
index 7a41213e1ce..a33b1e48233 100644
--- a/packages/react-art/package.json
+++ b/packages/react-art/package.json
@@ -1,7 +1,7 @@
 {
   "name": "react-art",
   "description": "React ART is a JavaScript library for drawing vector graphics using React. It provides declarative and reactive bindings to the ART library. Using the same declarative API you can render the output to either Canvas, SVG or VML (IE8).",
-  "version": "16.4.1",
+  "version": "16.4.3-alpha.0",
   "main": "index.js",
   "repository": "facebook/react",
   "keywords": [
diff --git a/packages/react-dom/package.json b/packages/react-dom/package.json
index 8fbb203d048..9f89e24c767 100644
--- a/packages/react-dom/package.json
+++ b/packages/react-dom/package.json
@@ -1,6 +1,6 @@
 {
   "name": "react-dom",
-  "version": "16.4.1",
+  "version": "16.4.3-alpha.0",
   "description": "React package for working with the DOM.",
   "main": "index.js",
   "repository": "facebook/react",
diff --git a/packages/react-is/package.json b/packages/react-is/package.json
index 9b41e5e81b0..09728faafe1 100644
--- a/packages/react-is/package.json
+++ b/packages/react-is/package.json
@@ -1,6 +1,6 @@
 {
   "name": "react-is",
-  "version": "16.4.1",
+  "version": "16.4.3-alpha.0",
   "description": "Brand checking of React Elements.",
   "main": "index.js",
   "repository": "facebook/react",
diff --git a/packages/react-test-renderer/package.json b/packages/react-test-renderer/package.json
index ff09dffa9a9..5ff1da8bf39 100644
--- a/packages/react-test-renderer/package.json
+++ b/packages/react-test-renderer/package.json
@@ -1,6 +1,6 @@
 {
   "name": "react-test-renderer",
-  "version": "16.4.1",
+  "version": "16.4.3-alpha.0",
   "description": "React package for snapshot testing.",
   "main": "index.js",
   "repository": "facebook/react",
@@ -17,7 +17,7 @@
   "dependencies": {
     "object-assign": "^4.1.1",
     "prop-types": "^15.6.2",
-    "react-is": "^16.4.1"
+    "react-is": "^16.4.3-alpha.0"
   },
   "peerDependencies": {
     "react": "^16.0.0"
diff --git a/packages/react/package.json b/packages/react/package.json
index 7be32deba4f..6c9ad1ad537 100644
--- a/packages/react/package.json
+++ b/packages/react/package.json
@@ -4,7 +4,7 @@
   "keywords": [
     "react"
   ],
-  "version": "16.4.1",
+  "version": "16.4.3-alpha.0",
   "homepage": "https://reactjs.org/",
   "bugs": "https://github.com/facebook/react/issues",
   "license": "MIT",
diff --git a/packages/shared/ReactVersion.js b/packages/shared/ReactVersion.js
index 47ea28d3492..865a46fe3fe 100644
--- a/packages/shared/ReactVersion.js
+++ b/packages/shared/ReactVersion.js
@@ -8,4 +8,4 @@
 'use strict';
 
 // TODO: this is special because it gets imported during build.
-module.exports = '16.4.1';
+module.exports = '16.4.3-alpha.0';