diff --git a/packages/react-devtools-core/package.json b/packages/react-devtools-core/package.json
index 39947c4177b..05df906770f 100644
--- a/packages/react-devtools-core/package.json
+++ b/packages/react-devtools-core/package.json
@@ -1,6 +1,6 @@
 {
   "name": "react-devtools-core",
-  "version": "4.12.0",
+  "version": "4.12.1",
   "description": "Use react-devtools outside of the browser",
   "license": "MIT",
   "main": "./dist/backend.js",
diff --git a/packages/react-devtools-extensions/chrome/manifest.json b/packages/react-devtools-extensions/chrome/manifest.json
index 64f3c0afe23..6e674216542 100644
--- a/packages/react-devtools-extensions/chrome/manifest.json
+++ b/packages/react-devtools-extensions/chrome/manifest.json
@@ -2,8 +2,8 @@
   "manifest_version": 2,
   "name": "React Developer Tools",
   "description": "Adds React debugging tools to the Chrome Developer Tools.",
-  "version": "4.12.0",
-  "version_name": "4.12.0",
+  "version": "4.12.1",
+  "version_name": "4.12.1",
 
   "minimum_chrome_version": "60",
 
diff --git a/packages/react-devtools-extensions/edge/manifest.json b/packages/react-devtools-extensions/edge/manifest.json
index d78048924e4..5e125ead626 100644
--- a/packages/react-devtools-extensions/edge/manifest.json
+++ b/packages/react-devtools-extensions/edge/manifest.json
@@ -2,8 +2,8 @@
   "manifest_version": 2,
   "name": "React Developer Tools",
   "description": "Adds React debugging tools to the Microsoft Edge Developer Tools.",
-  "version": "4.12.0",
-  "version_name": "4.12.0",
+  "version": "4.12.1",
+  "version_name": "4.12.1",
 
   "minimum_chrome_version": "60",
 
diff --git a/packages/react-devtools-extensions/firefox/manifest.json b/packages/react-devtools-extensions/firefox/manifest.json
index fa8dc48ca41..c02e8cc9042 100644
--- a/packages/react-devtools-extensions/firefox/manifest.json
+++ b/packages/react-devtools-extensions/firefox/manifest.json
@@ -2,7 +2,7 @@
   "manifest_version": 2,
   "name": "React Developer Tools",
   "description": "Adds React debugging tools to the Firefox Developer Tools.",
-  "version": "4.12.0",
+  "version": "4.12.1",
 
   "applications": {
     "gecko": {
diff --git a/packages/react-devtools-inline/package.json b/packages/react-devtools-inline/package.json
index 334c65e51ea..876ffdc51b4 100644
--- a/packages/react-devtools-inline/package.json
+++ b/packages/react-devtools-inline/package.json
@@ -1,6 +1,6 @@
 {
   "name": "react-devtools-inline",
-  "version": "4.12.0",
+  "version": "4.12.1",
   "description": "Embed react-devtools within a website",
   "license": "MIT",
   "main": "./dist/backend.js",
diff --git a/packages/react-devtools-inline/src/frontend.js b/packages/react-devtools-inline/src/frontend.js
index ebd57022e69..a4c7f61f223 100644
--- a/packages/react-devtools-inline/src/frontend.js
+++ b/packages/react-devtools-inline/src/frontend.js
@@ -91,7 +91,7 @@ export function initialize(
   window.addEventListener('message', onGetSavedPreferencesMessage);
 
   if (bridge == null) {
-    bridge = createBridge();
+    bridge = createBridge(contentWindow);
   }
 
   if (store == null) {
diff --git a/packages/react-devtools/CHANGELOG.md b/packages/react-devtools/CHANGELOG.md
index 3d83a269dce..f2f038e94cd 100644
--- a/packages/react-devtools/CHANGELOG.md
+++ b/packages/react-devtools/CHANGELOG.md
@@ -9,6 +9,11 @@
   <!-- Upcoming changes go here -->
 </details>
 
+## 4.12.1 (April 14, 2021)
+Although this release is being made for all NPM packages, only the `react-devtools-inline` package contains changes.
+#### Bugfix
+* Fixed `react-devtools-inline` bug in frontend `initialize` method ([bvaughn](https://github.com/bvaughn).
+
 ## 4.12.0 (April 12, 2021)
 Although this release is being made for all NPM packages, only the `react-devtools-inline` package contains changes.
 #### Feature
diff --git a/packages/react-devtools/package.json b/packages/react-devtools/package.json
index 593850e753d..cfaec58b64f 100644
--- a/packages/react-devtools/package.json
+++ b/packages/react-devtools/package.json
@@ -1,6 +1,6 @@
 {
   "name": "react-devtools",
-  "version": "4.12.0",
+  "version": "4.12.1",
   "description": "Use react-devtools outside of the browser",
   "license": "MIT",
   "repository": {
@@ -27,7 +27,7 @@
     "electron": "^11.1.0",
     "ip": "^1.1.4",
     "minimist": "^1.2.3",
-    "react-devtools-core": "4.12.0",
+    "react-devtools-core": "4.12.1",
     "update-notifier": "^2.1.0"
   }
 }